PLATINUM METALS REVIEW
A quarterly survey of research on the platinum metals and of developments in their applications in industry
VOL. 12 OCTOBER 1968 NQ. 4
Conten fs
Sliding Noble Metal Contacts
Platinum Metal Contacts
Nitrosyl Complexes of the Platinum Metals
Phase Equilibria in the Platinum-Molybdenum System
Phosphine Complexes of Khodium and Ruthenium as Homogeneous Catalysts
Fourth International Congress on Catalysis
Therrnochemistry of the Platinum Metals and their Compounds
One Million Ounces of Platinum
Hydrogen in Palladium and its Alloys
Hydrogen Diffusion through Rhodium-Palladium Alloys
The First Platinum Refiners
Abstracts
New Patents
Index to Volume 12
Communications should be addressed to The Editor, Platinum Metals Reviau Johnson, Matthey & Co., Limited, Halton Garden, London, E.C.1 Sliding Noble Metal Contacts
CONTACT RESISTANCE AND WEAR CHARACTERISTICS OF SOME NEW PALLADIUM ALLOY SLIDEWIRES
By A. S. Darling, Ph.D., A.M.I.Mech.E., and G. L. Selnian, BS~. Research Laboratories, Johnson Matthey & Co Limited
stationary wiper to establish the necessary Vhen, as in many low torgue potentio- sliding contact. meters, contact pressures must not The wiper wire is approximately 0.010inch exceed a feu' grams the use of noble in diameter and contact pressures, in the metals for both resistance mire and range from 0.1 to 10 grams, are adjusted by wiping coratact becomes almost essential. lowering the pendulum suspension until As the factors that determine the elw flexure of the cantilever produces the load trical and mechanical behaviour of such required. After such adjustment the pendu- lotv load sliding contacts have not yc.t lum is rigidly clamped so that well defined been pstablished, zuiperlslidetoire corn- wear tracks are obtained on the wire under binations are still selected on an em- test when the bobbin is reciprocated. pirical basis. This paper, baced on a Coefficients of friction are determined by lecture recently delivered to the Fourth unclamping the pendulum and measuring the Internutional Research Symposium on angular deflections which result when the Electrical Contact Phenomena at Swan- coil of resistance wire is moved below the sea, descrihes some results obtained on wiper. With the experimental arrangement an apparatus in which the abrasion employed a tangential force of 0.2 gram resistance and frictional characteristics corresponds to a pendulum displacement of of precision resistance alloys can he I" and is therefore easily measured with the assessed in un objective manner at very optical lever. lozv contact loads. Irnder such condi- Current is led into the wiper through a tioris metal is transjerred from wiper to separate current lead which constitutes one resistance alloy and the eficiency of this arm of the bifilar tape suspension. The transfer process determines the electrical potential lead, attached to the other side of behnviour of these slidir~gcontacts. the wiper hairpin, passes out through the other suspension. By this method contact resistances are accurately determined by the A general view of the apparatus employed four-mire method. is given in Fig. I. As shown diagram- The equipment employed is surrounded by matically in Fig. a, the wiping contact is in a gas-tight metal and glass container in which the form of a bent hairpin. Mounted as a organic materials are largely avoided. The cantilever, it is clamped below the bob of a chamber can if required be evacuated and compound pendulum and pressed against back-filled with any desired atmosphere, and the contact track which has been prepared equipment is provided for varying the internal on the surface of an aluminium bobbin, humidity. Being suspended from long, closely wound with the resistance wire under elastic, nylon ropes the equipment is effec- test. This coil is reciprocated below the tively isolated from most vibrations.
Platinum Metals Rev., 1968, 12, (4), 122-128 122 Fig. 1 General view of the apparatus used for wear and contact resistance measurements OIL noble metal slidewire rriuterials
The solid solution alloy containing 40 per cent of silver and 60 per cent of palladium is very widely used for precision resistance purposes as it combines a moderately high resis- tivity with low contact resistance and a very low temperature coeffi- cient of resistance. Silver-palladium has therefore been used as a stan- dard of reference in this investiga- tion, where its characteristics in the annealed and work-hardened con- dition have been compared with those of vanadium-palladium and molybdenum-palladium-gold alloys.
In all the tests reported a gold-silver- copper alloy (625 alloy) was used for the wiping contact. The composition and electrical characteristics of the various alloys investigated are summarised in the table overpage, which also defines the metallurgical condition in which these materials were actually tested.
Static Contact Resistance These experiments were made in the normal laboratory atmosphere which was not dried before ad- mission to the apparatus. The re- sistance alloys were tested in the form of a thin sheet which was wrapped round the drum normally used for testing wire. Apart from careful degreasing before test no attempt was made to improve on the high quality rolled finish of these sheets.
Platinum Metals Rev., 1968, 12, (4) 123 I Physical Properties of the Alloys Investigated Specific remperature U.T.S. and Hardness Resistance coefficient
Alloy ~ of resistance Annealed Hard I2jcirc (0-1 00°C) ~ miljft per "C 40 per cent Silver-palladium 42 252 0.00003 38 70 100 270 5 per cent Molybdenum- 100 600 0.0001 2 150 110 31 0 40 per cent palladium-gold 68 9 per cent Vanadium-palladium 150 900 -0.00008 78 190 140 390 Fine silver 1.6 9.6 0.0041 14 24 - - 62.5 per cent Au/Cu/Ag wiper 14 84 - - - 70 220 alloy - - Some of the effects of load and wiping on palladium the initial fall in contact resistance the static contact resistance of fully annealed occurred very rapidly. Steady conditions specimens are shown in Fig. 3. These were arrived at with loads of about five grams resistance measurements were made with a and little change in contact resistance occurred constant current of 50 milliamps, and the high at higher pressures. The harder vanadium- resistance values determined at loads below palladium and molybdenum-palladium alloys one gram were found to decrease very rapidly did not arrive at steady conditions so rapidly, as the contact load increased. With soft and as shown in Fig. 4 the resistance still materials such as fine silver and silver- fell significantly at contact loads of ten grams. Platinum Metals Rev., 1968, 12, (4) 124 These well defined relationships between contact resistance and load for noble metal alloys are in complete contrast to the uncer- tain behaviour experienced with base metal resistance wires. The experimental values plotted in these curves were obtained for increasing loads. Slight hysteresis effects occurred during unloading when the loads fell below threc grams, although the effect was not pro- nounced and was barely detcctable with the molybdenum-palladium and vanadium- palladium alloys. Static contact resistances fell significantly after sliding had occurred. The behaviour of work hardened and annealed silver- palladium alloys is shown in Fig. 3, where the effects of wiping under a 7 gram load can be observed. Decrements in contact resistance of up to 50 per cent occurred simply as a result of relative movement between the two contacts. Steady conditions were arrived at after approximately one hundred wiping operations, and subsequent work showed that this effect was not greatly influenced by the magnitude of the wiping load. After wiping, the contact resistances of the silver-palladium and molybdenum-palladium-gold alloys became comparable in magnitude at loads above 5 grams. Although it was originally felt that this reduction in contact resistance was due to the removal of adsorbed and combined sur- face films, detailed examination of the wear tracks obtained showed that rapid material transfer occurred during wiping and that a large proportion of the resistance decrement could be accounted for in this way. This After about one hundred wiping operations, subject is discussed later in the paper. however, the dynamic and static values begin to converge and over the range IOO to 3,000 Sliding Contact Resistance operations both values remain at a con- In the early stages of operation the sliding sistently low level, which for silver-palladium Contact resistance is appreciably higher than is almost independent of the wiper load the statically determined value, and as imposed. shown in Fig. 5 this difference is more After approximately 3,000 wiping opera- pronounced with a soft material, such as fully tions high dynamic contact resistances tend to annealed silver-palladium, than with a hard develop on materials tested at loads below alloy such as molybdenum-palladium-gold. 3 grams. Fully annealed silver-palladium, Platinum Metals Rev., 1968, 12, (4) 125 run on a I gram load showed this effect to a high degree, although it behaved in a very satisfactory manner with a 7 gram load. Under low load conditions the work-hardened silvcr-palladium alloy performed better than the fully annealed material and discrepancies between the statically and dynamically deter- mined contact resistances were very much less. Peak to peak noise, as indicated by the oscilloscope, showed the same general trends, and in the case of fully annealed silver- palladium working under a one gram load approached values equivalent to a resistance of 0.5 ohms during the latter stages of the test. At intermediate loads the molybdenum- palladium-gold alloy, with a specific resistance of IOO $1 cm, was shown to be equal to silver- palladium in its contact performance. The vanadium-bearing alloy displayed some un- usual characteristics; during the initial wiping period sliding contact resistances and noise levels rose steeply, the former reaching values of several ohms in some instances. After one hundred wipes with a 7 gram load, however, the sliding contact resistance and noise level dropped rapidly and approached closely the normal static values. Wear and Metal Transfer Microscopic examination of the wear tracks on the sheet specimens showed a fairly broad shallow furrow with a continuous row of wear fragments thrown out on each side of the track. Fig. 6a shows one side of Fig. 6 Appearance and composition of such a track with its associated bank of debris. worn surfaces. Fig. 6a (top) shows the visual appearance of the right hand side of the wear Microprobe analysis of this groove and many furrox on a work hardened silver-palladium others in all the palladium alloys tested specimen. ( x 350). Fig. 66 (centre) shows at showed that smears of the transferred gold the same rnagnificatLon the dibtribution oj gold transferred to this surfare from the alloy existed over the complete abraded wipes, while Fig. 6c (bottom) shows the worn surface. On the silver-palladium alloys this surface of the 625 alloy wiper which pro- film was virtually continuous as indicated duced this track. ( x 150) by Fig. 6b which provides a gold Krx-ray image of the surface of the track shown in film was less uniformly distributed although Fig. 6a. This track had been formed on a still present. In all instances the gold/copper work-hardened silver-palladium specimen ratio in the transferred film was the same as after 30,000 wipes with a 7 gram load. At that existing in the wiper alloy. lower loads, and on the resistance alloys In Fig. 6c can be seen the worn area of the containing base metal additions, this gold wiper which produced the wear track in Platinum Metals Rev., 1968, 12, (4) 126 Fig. 6a. The foil-like metal fragments hanging from the periphery of the wear area are of the same composition as the wiper, and no evidence of palladium transfer from resistance alloy to wiper was detected in any of the ex- periments except those made on fully an- nealed silver-palladium. In such instances traces of silver-palladium were detected on the leading and trailing edges of the wiper but not on the worn area. Obvious “prows” of pure silver were also detected when wear tests were made on this pure metal. Although the worn area of the wiper provided a rough indication of the quantity of metal removed, no correlation has yet been established between the rate of wiper wear Fig. 7 Wear tracks on a potentiometer wound and the hardness or composition of the with silver-palladium wire ( X 300) resistance alloy against which it had been abraded. resemble those referred to above. The track Silver-palladium potentiometer windings illustrated in Fig. 7 shows the extensive that have been in service for many thousands plastic deformation that occurs. Metal is of operations show wear tracks which closely moved over laterally in the direction of wiping and eventually begins to short circuit adjacent turns. For this reason serious wear in close-wound slidewire potentiometers is usually accompanied by a rapid fall in total resistance. Discussion and Conclusions This report is based on what must be regarded as the preliminary results of a rather wider investigation and it would be unwise therefore to draw too many specific conclusions from the data presented. It has been established, however, that under rub- bing loads of less than ten grams metal is transferred from the wiper to the resistance alloy and it appears that, after a brief period of sliding, electrical contact is established between the wiper and a thin film of the wiper alloy spread out on the resistance alloy surface. The results of tests in which 625 alloy was used both as a wiper and as a resistance alloy supported this conclusion. Some of the con- tact resistance curves obtained are shown in Fig, 8. Before wiping, values of contact re- sistance were measured which, for a given Platinum Metals Rev., 1968, 12, (4) 127 load, closely resembled those of the 625 beneficial results are undoubtedly obtained alloy/silver-palladium combination after wip- by the use of noble metal slidewires the con- ing. Although subsequent sliding reduced tact resistances provided by such combina- slightly the contact resistance of the 625 alloy tions are at low loads still many times higher combination, significant decrements in resist- than those available from noble metal wire. ance occurred only at very low loads and after The vanadium-palladium (I) alloy dis- 100 wiping operations the contact resistance played a contact resistance which, although curve became almost coincident with that of initially a little higher than that of silver- the wiped silver-palladium resistance alloy. palladium, decreased rapidly on wiping and It seems evident therefore that the initial settled down at an acceptably low level. The static contact resistance of wiper against molybdenum-palladium-gold alloy (2) is resistance alloy does not provide a realistic unique in combining a very high specific indication of contact performance. After resistance with a contact resistance which, sliding under low load conditions, as in the after one or two wiping operations is no higher present experiments, metal transfers from than that of silver palladium. The success of wiper to slidewire and because of this effect this alloy as a slidewire material might well we are really testing the performance of this be attributable to its duplex microstructure, wiper alloy rubbed against itself. Viewed in one phase of which contains a high proportion this way it is easy to understand why all the of gold. palladium alloys tended, after a little rubbing, Although no quantitative correlations have to develop similar contract resistances. This yet been established between the mechanical finding has an important bearing on resistance properties of the resistance alloys and their alloy development as it appears to suggest wear characteristics this subject obviously that within the same general range of com- merits closer attention. None of the wear position new and improved resistance alloys tracks examined were more than two microns could be selected on the basis of their bulk deep, and it is certainly true to say that for electrical resistivity and temperature co- any given condition of test the harder alloys efficient, as contact resistances will be deter- showed rather shallower grooves than the fidly mined largely by the properties of the wiping annealed silver-palladium alloy. Although alloy employed. the wear tracks showed on their surface a This generalisation applies, however, only parallel series of micro-furrows, no corres- when the noble metal resistance alloy contains ponding serrations occurred on the wiper and low concentrations of base metals. When the it appears very probable that, as suggested by alloying elements have a tendency to form Antler (3), the transferred metal does not stable oxides, metal transfer from the wiper is adhere well to the smaller surface. Our results less efficient and higher contact resistances differ from those of Antler in that metal are encountered. transfer was invariably from wiper to resist- This effect becomes detectable with the ance alloy even when the wiper was consider- vanadium-palladium alloy where electron ably harder. Such differences are probably probe examination showed that the trans- attributable to the low contact pressures ferred film of gold-based wiper alloy was employed in this work. rather less uniformly distributed than on the silver-palladium or molybdenum-palladium- gold alloys. Even so, the measured contact References resistances were only marginally higher. I Johnson Matthey, Prov. Pat. 21853167 Noble metals from the wiper are not, 2 Johnson Matthey, B.P. 861,646 however, effectively transferred to base metals 3 M. Antler, Mechanisms of Solid Friction, Elsevier Pub. Co, London, 1964, pp. 181-203; such as nickel-chromium, and although Platinum Metals Rev., 1966, m, 2 Platinum Metals Rev., 1968, 12, (4) 128 Platinum Metal Contacts PAPERS AT THE FOURTH INTERNATIONAL SYMPOSIUM ON ELECTRICAL CONTACT PHENOMENA Platinum metals and their alloys featured in many of the $.papers presented at the Fourth Interhational Symposium, sponsored jointly by the Institute of Physics and the Physical Society and the Institution of Electrical Engineers, held in July at the University College of Swansea. The characteristics of the surface films that and wear characteristics of some new palla- may form on palladium, platinum and electro- dium alloy slidewire materials presented deposited rhodium surfaces and their effects interesting data, and is published in an en- on adhesion and contact resistance under loads larged and revised version in this issue. of less than I gram were examined by H. C. Angus of the International Nickel Company. Molten Bridges between Using a loop of fine wire which could be Separating Contacts lowered into contact with a flat surface and The small molten bridges that may form subsequently withdrawn, it was found that, and briefly bridge the surfaces of a separating under very small loads of a few milligrams, contact have for many years been the subject electrical contact resistivity was high and there were few signs of adhesion between platinum and either platinum, palladium or rhodium. With loads above about 50 milli- grams, however, strong cold adhesion was observed between the loop and the flat metal surface, and the contact resistance rapidly fell to very low values. bridge It is evident that under very low loads sur- face films interfere with the establishment of true metal-to-metal contact. Generally speak- ing, if the temperature of the contact surfaces is raised, the load required to cause adhesion becomes progressively lower, probably due to softening of the constriction areas of contact and to stretching of the surface films. The effect, however, may be complicated by the Rupture tendency of the films to thicken by oxide growth at temperatures up to about 600°C. At still higher temperatures, the oxide films Scattering of decompose and welding becomes more easily molten drops effected. The method of test used in this in- from ruptured bridge vestigation has been particularly valuable in showing a fundamental difference between Disruption of molten bridge between separat- the surface films on gold and on the platinum ing platinum contacts in helium, breaking metals. a direct current of 100 amperes at h volts. (Capacitance 4 F, inductance 0.06 H). A paper by A. S. Darling and G. L. Selman 9000 frames per second, x 26. (Courtesy of of Johnson Matthey on the contact resistances Dr F. LEewellyn-Jones.) Platinum Metals Rev., 1968, 12, (4), 129-130 129 of special study by the research workers in surface deformation caused by repeated the Department of Physics at the University closure on the electrical resistance of the College of Swansea under the general direc- surface films on contact surfaces operating in tion of the Principal, Dr F. Llewellyn-Jones. air. They have been particularly concerned The recent development in this laboratory of with the pattern of the resistance changes an ultra-high-speed camera capable of taking which are observed and have attempted to up to 20,000 pictures at IOO,OOO frames per correlate fluctuations with the mode of pene- second has revealed some hitherto unsus- tration or fracture of the protective films. pected details of the process of rupture. A film shown by Dr Lewellyn-Jones in his Deterioration of Metallic Contacts introductory lecture to the symposium and Of more general interest, the deterioration described later by Dr B. R. Thomas, reveals of the electrical resistance between two that the molten bridge between platinum con- metallic butting connectors was displayed tacts may rupture and reform once or more most convincingly by Dr J. B. Williamson of times during the separation of the contacts the Burndy Research Laboratory, Norwalk, before the electrical circuit is finally broken. Connecticut, in an outstanding address. He With platinum contacts, this behaviour is all demonstrated that since only a few point con- the more remarkable since no liquid or solid tacts normally provide the constrictive resist- oxides can be present to introduce compli- ance and carry the whole of the electrical load, cations. A fascinating picture emerges of a intersurface corrosion may proceed for minute maelstrom of forces which are let months or years without noticeable effect on loose for a few micro-seconds in a cloud of the current carrying capacity of the connector. platinum vapour and whirling electrons when- The hal stages of corrosion, however, may ever a pair of platinum electrodes is opened then cause complete electrical failure in a to interrupt an electrical circuit. dramatically short period. Contact Operation New Techniques The action of opening and closing make- Among new techniques, scanning electron and-break contacts in breaking up and other- microscopy by reason of its great depth of wise disturbing the films on the contact focus would seem to have considerable surfaces was considered in more than one of promise as a means of studying surface the contributions to the symposium. Dr changes produced by the operation of elec- H. W. Dinges and Dr H. Schmidt-Brucken, trical contacts. A paper by T. A. Davies of of Darmstadt, reported microscopical studies the Allen Clark Research Centre of the of the brown polymer film which forms on Plessey Company Limited, Caswell, showed platinum metal contacts operating in organic examples of the detail obtainable by this vapours. The monomolecular layers first means. formed were seen to be brushed aside by local Finally, mention should perhaps be made rubbing movements and often built up into of a series of palladium alloys, proposed on small heaps around the actual contact areas. theoretical grounds by Professor K. Mano of In these circumstances contact failure may Tohoku University, Sendai, Japan, and T. only develop slowly and at irregular intervals, Hare, of Fujitsu Limited, as being of high a conclusion supported by statistical studies resistance to corrosion and organic polymer of the contact resistance of relays operated fornation. They consist of palladium alloys for several million switching movements. with less than about 12 per cent of silver, Dr A. Fairweather, Mr F. Lazenby and Mr copper, tin or antimony so that the @ band D. Marr of the Post Office Research Station, of palladium is fdled with valence electrons London, have also studied the effects of the of one or more of these metals. J. C. C. Platinum Metals Rev., 1968, 12, (4) 130 Nitrosyl Complexes of the Platinum Metals By M. J. Cleare, A.R.c.s., BS~. Research Laboratories, Johnson Matthey & Co Limited nearer the latter in most cases. The nitrosyl In recent years much research has been group is also a strong T;-acceptor (stronger carried out on platinum group metal than CO) and the filled metal d orbitals will complexes, especially those containing tend to overlap with the empty antibonding the carbonyl ligand. As the nitrosyl molecular orbital of the ligand to give the group is a nitrogen bonded ligand which M-N bond a degree of multiple character. This in its normal mode of bonding is is nicely demonstrated by a neutron diffraction isoelectronic with carbon monoxide, the study on Na,[Ru(NO)(OH)(NO,),].zH,O chemistry of complexes containing co- (3). The Ru-NO bond length of 1.748A is ordinated nitric oxide is interesting, and much shorter than might be expected for they may haze similar potential uses to single bonding as is shown in the same the carbony1 complexes. This article complex by the Ru-NO, bond which is outlines our present knowledge of the 2.07gA in length. The Ru-N02 bond is nitrosyl complexes and their mode of very largely of single-bond character. All bonding. the platinum metal complexes are con- sidered to be bonded in the NO+ manner. Nearly all nitrosyl complexes contain only The nitric oxide molecule is unusual in that one nitrosyl group and this is especially so for it has an odd number of electrons (namely IS), the platinum metals. The most likely ex- one of which is housed in an anti-bonding planation for this is that the x-acceptor ability molecular orbital. It may lose this electron of the ligand is so great that more than one relatively easily to give NO?, a species group might remove an excessive amount of isolelectronic with molecular introgen as well electron density from the metal. Simple as carbon monoxide. Simple nitrosonium binary compounds M,(NO), unlike the salts such as NO'ClO-, are quite stable. carbonyls, are unstable, the only reported one In the majority of nitrosyl complexes the being prepared from Ru,(CO),, with nitric ligand may be considered as NO with the oxide at 190°C and 320 atmospheres of odd electron being transferred to the metal, pressure (4). There is considerable doubt as thus decreasing its formal oxidation state by to the composition of the red crystals formed; one. The nitrosonium ion co-ordinates to they may be Ru(NO), analogous to the iron the metal by donation of an electron pair in nitrosyl, [RuNO,], or even a carbonyl an sp orbital of the nitrogen atom completing nitrosyl. No definite carbonyl nitrosyl com- a bond in which three electrons arc involved. plexes have yet been prepared, which seems This is a simplified picture of the bonding, for surprising considering the known compounds e.s.r. studies (I, 2) have indicated that the odd of nickel, iron and cobalt, and investigation electron does spend a small amount of time into such compounds may well be reward- on the nitrosyl ligand, and thus the true ing. The only other compounds containing nature of the bonded ligand lies between more than one nitrosyl group are the chloro- neutral NO and NO+ although very much bridged species Rh-1(NO)2X (X=C1, Br, I), Platinum Metals Rev., 1968, 12, (4) 131-133 131 the tetrahedral Pd”(NO),Cl, and also some acid on the nitrite complex. These species nitrosyl phosphine complexes of iridium. are particularly interesting as they are ex- The compounds Rh-l(NO), X are prepared tremely soluble in organic solvents and have by the action of nitric oxide on the corres- been used to remove ruthenium by solvent ponding carbonyl halide Rh(CO),X (X =C1, extraction. Trihalo complexes [RuNOX ,In Br, I) at 60°C (5, 6); they are black amor- .nH,O are produced by evaporating RuO, phous powders which are thought to be with hydrochloric and nitric acids. A wide tetrameric. Pd(NO),Cl, is obtained by pass- range of compounds of formulae RuNOCl,L, ing nitric oxide, laden with methanol vapour, (L =phosphines, arsines and stibines) may be over solid palladous chloride (7). It is un- prepared from [RuNOCl,], (9). Ruthenium (I) stable, evolving nitric oxide at high tempera- complexes [RuNOX,], (X=Br, I) can be tures or in moist air. A sulphato complex made by the action of nitric oxide at 23oOC Pd(NO),SO, is also known (7). on [R~(c0)&2In(10). The mononitrosyl complexes will be con- sidered metal by metal: Osmium Osmium complexes are far less numerous Ruthenium than those of ruthenium, which is somewhat Ruthenium nitrosyl complexes are more surprising as recent work in these laboratories numerous than those of any other element has indicated that the 0s-NO bond may be (over one hundred are known). They are all stronger than Ru-NO and more stable to octahedral with the Ru-NO group having a certain types of reaction, especially reduction formal charge of +3. The metal-nitrogen (11). A nitrite complex K,[OsNO(OH) bond is extremely difficult to break whether (NO,),] may be prepared by the prolonged the complex is anionic, neutral or cationic, and action of potassium nitrite on K,OsCl,, and reactions normally involve exchange of the reaction of this with hydrohalic acids gives other five ligands. The formation of the halides [OsNOXJ- (X=Cl, Br, I) (12). metal-nitrosyl bond is so favoured that An intermediate in the chloro reaction reactions of ruthenium compounds with K,[ OsNO(N0,) ,C1 ,] has recently been NO, NO,, NO; or HNO, almost always isolated in these laboratories (I I). It seems lead to its production. A very useful start- likely that other osmium(I1) nitrosyl com- ing product for many other complexes is pounds will be prepared, probably in a similar Na,[Ru NO(OH)(NO,),] which is prepared manner to the ruthenium analogues but using from ruthenium trichloride and sodium nitrite more extreme conditions to overcome the in the presence of a small amount of hydro- kinetic inertness to substitution of the third chloric acid (8). Treatment of these yellow row transition metal complexes. crystals with the appropriate hydrohalic acid yields [RuNOX5Iz- (X=Cl, Br) and Rhodium treatment of the latter with other ligands such Very few compounds are known; the only as CN- and NCS- gives rise to further com- reported ones are from the reaction of plexes of type [RuN0L5l2- by ligand ex- [Rh(NO),Cl], and phosphine type ligands change. Reaction with ammonia gives giving [Rh NO L3] and [Rh NO L,Cl,] (13). hydroxy ammines [Ru(NH,) ,NO(OH)]X, It is believed that [RhNOCN5I3-is formed in (X-C1, Br, I); a pentammine may be pre- the reaction of [Rh(NO),Cl], with alkali pared from either [Ru”(NH,),]Cl, or cyanides (14). No rhodium(II1) complexes [Ru”‘(NH,),Cl]Cl, by reaction with sodium are known; the reaction of hydrochloric acid nitrite and hydrochloric acid. Nitrate com- with the nitro complexes [Rh(NO,),X 6-y]s- plexes [RuNO(N0,)y(OH)3-y(HzO),1 (Y= (y=6, 4, 2) yields only the hexachloro com- I, 2 or 3) are produced by the action of nitric pound. Platinum Metals Rev., 1968, 12, (4) 132 Iridium crystals of K,[PtNOCl,] (18). A similar Thc nitrosyl chemistry is again limited and pentacyano compound has been made by the only simple complexes are the halides ligand exchange. Other complexes containing [Ir NOX,]- (X=Cl, Br) which are prepared arnmine, nitro and nitrato ligands have been by the action of hydrohalic acid on the nitro similarly prepared; [PtNO(NH,),Cl]Cl, may complexes [Ir(NO,), X,-,I3- (y=2, 3, 4 or 6) be made from NOCl and [Pt(NH,),]Cl,, (I I, 15). Although anionic, these complexes K,[PtNO(KO,),CI] from NOCl and (especially the bromide) are soluble in organic KA"O,),I and KJPt NO(NOz)J'JO31 solvents. Some interesting nitrosyl phosphines from K,Pt(NO,), and nitric acid (18). The are also known and these contain iridium in general instability of these compounds is not formal oxidation states varying from I1 to surprising as they are the only known -11 (16). The action of nitric oxide on examples of six co-ordinate platinum (11). [Ir H,(PPh,),] C10, gives [Ir-1(NO),(PPh3),1 For further reading the following excellent C10,. Subsequent reaction with lithium reviews are recommended: halides gives [Ir-l(NO),(PPh,),X] (X =C1, Transition Metal Nitrosyl Complexes, B. F. G. Br, with bromine gives [Ir"(NO)Br, Johnson and J. A. McCleverty. Progress in I), Inorganic Chemistry, Vol. 7 (Interscience, (PPh,),] and hydrohalic acids (II(N0) 1966) X,(PPh,),] (X=Cl, Br, I). Nitric oxide with Organometallic Nitrosyls, W. P. Griffith. Advances in Organometallic Chemistry, Vol. [Ir H ,(PPh ,) ,] gives (Ir-"(NO) ,PPh,]. 7. Shortly to be published. Palladium References Apart from Pd(NO),Cl, only a bridged I P. T. Manoharan and H. B. Gray, Inorg. polymer [PdNOCl], and a mixed nitro- Chem., 1966,5, 823 nitrato complex are known. The former is 2 E. F. Hockings and I. Bernal, 3. Chem. Soc., prepared by the action of nitric oxide on 1964,5029 3 S. H. Simonsen and M. H. Mueller,J. Inorg. palladous chloride or by the interesting re- Nuclear Chem., 1965, 27, 309 action between palladous chloride, sodium 4 W. Manchot and W. J. Manchot, 2. Anorg. Allgem. Chem., nitrite and an olefin, where the intermediate 1936,226,388,410 5 W. Manchot and H. Konig, Bm., 1937, 60, nitro complex reacts with the olefin, to 2130 produce a ketone (17). 6 W. P. Griffith, J. Lewis and G. Wilkinson, 3. Chem. SOC.,1959, 1775 [Pd (Cl) (NO,) XJ"+t-R CH=CHZ+ 7 W. Manchot and H. Waldmuller, Ber., 1926, PdNOC1+2X- +RCOCH, 59,2363 8 J. M. Fletcher, I. L. Jenkins, F. M. Lever, (X=Cl or OH) (R=H or alkyl) F. S. Martin, A. R. Powell and R. Todd, J. Inorg. Nuclear Chem., 1955, I, 378 [PdNOCl], reacts with ammonia and 9 J. Chatt and B. L. Shaw, J. Chem. Suc., (A), cyanide ion to lose the nitrosyl ligand and 1966, 1811 form complexes [Pd(CN)J2- and I0 W. Manchot and H. Schmid, Z. Anorg. Allgem. Chem., 1933, 216,99 [Pd(N&)4I '- I1 M. J. Cleare and W. P. Griffith, to be pub- K,[Pd(NO,),(NO,)NO] is formed by the lished action of nitric acid on K2PdK'(NOp)4and I2 L. Wintrebert, Ann. Chim. Phys., 1903, 28, (7L is a red-brown air stable substance (IS). 15 13 W. Hieber and K. Heinicke, 2.An0l.g. Allgem. Chem., 1962, 316,321 Platinum 14 W. P. Griffith, unpublished results 15 L. Malatesta and M. Angoletta, Angew Chem., Platinum forms a number of unstable octa- 1963,2,I55 hedral complexes with the metal formally in the 16 L. Malatesta, M. Angoletta and G. Caglio, divalent state. Potassium chloroplatinite(I1) Angew Chem., 1963,2,739 J. Smidt and R. Jira, Be., 1960,93, 162 reacts with nitrosyl chloride NOCl in 17 I8 W. P. Griffith, J. Lewis and G. Wilkinson, chloroform on long shaking to give green J. Chem. Soc., 1961,775 Platinum Metals Rev., 1968, 12, (4) 133 Phase Equilibria in the Platinum-Molybdenum System SIGNIFICANCE IN THE GLASS INDUSTRY The practical significance of the high tem- investigations which have previously been perature phase relationships in the platinum- made. molybdenum binary system has been dis- Seven single-phase regions are shown in the cussed in two recent articles in this journal, new diagram, which was determined by con- (I), (2), which described the way in which ventional metallurgical techniques using arc- platinum-clad molybdenum glass handling melted alloy buttons. The molybdenum-rich equipment can fail at temperatures above A15 phase, whose formation is thought to be 1300T by creep of the protective sheath if largely responsible for the high interfacial high temperature intermetallics are allowed strains developed in the platinum claddings to form on its inner surface. The inter- of molybdenum glass stirrers, is shown to pretation of the interfacial diffusion zone form via a peritectoid reaction between the microstructures observed during these investi- b.c.c. Mo solid solution and a disordered form gations was made more difficult by the lack of the hexagonal intermediate phase, origin- of sound information on the binary system ally observed by Raub (4), at approximately between the two metals, and it is pleasing to 18oo"C, and to decompose eutectoidally at note, therefore, that a thorough investigation approximately 13oo0C, forming a duplex recently carried out by H. Ocken and J. H. N mixture of the terminal molybdenum-rich Van Vucht in the Philips Research Labora- solid solution and the ordered hexagonal tories at Eindhoven (3) has resulted in the phase. presentation of a phase diagram for the It must surely be more than a coincidence platinum-molybdenum system which serves that the decomposition temperature of this to bring into perspective the many partial phase corresponds closely with what is 2400'"Oh The new phase diagram for the plat- inum-molybdenum binary system put -, 10 20 30 40 50 60 70 80 90 I 0 forward by IT. Ocken and J. 11. N. ATOMIC PER CENT PLATINUM Vun Vucht Platinum Metals Rev., 1968, 12, (4), 134-135 134 regarded as the maximum long-term operating confirmed experimentally some time later (I). temperature of a conventional platinum-clad At the platinum-rich end of the system, molybdenum component in the glass industry. the new diagram indicates the existence of a The investigators at Philips paid particular second orthorhombic phase, of approximate attention to the formation and properties of composition Mo Pt,. This structure appears this molybdenum-rich compound. An alloy to be an ordered form of the terminal face- containing 28 atomic per cent platinum was centred cubic platinum solid solution, and shown to be superconducting. The highest occupies the position formerly ascribed to the superconductive transition temperature for tetragonally distorted phase denoted z1 by this eutectic composition, 5.6”K,was observed hub (4). G. L. S. after annealing the alloy at 18oo3C. Other significant features of the diagram References include a proposed orthorhombic phase of I 6. L. Selman, Platinum Metals Rev., 1967, 11, equiatomic composition, stable at tempera- (41, 132 z A. S. Darling and G. L. Selman, Platinum tures below 13oo0C, and an extensive solu- Metals Rev., 1968, 12, (3), 92 bility of platinum in molybdenum. The latter 3 H. Ocken and J. H. N. Van Vucht, J. Less- finding is of interest in that it was originally Common Metals, 1968, 15, (2), 193 4 E. Raub, 2. Metallk., 1954, 45, 23 predicted on theoretical grounds by means of 5 W. Hume-Rothery, Progress in Materials the Engel-Brewer correlation (5), and was Science, 1967, 13, (5), 231 Phosphine Complexes of Rhodium and Ruthenium as Homogeneous Catalysts HYDROFORMnATION OF OLEFINS One of the most rapidly advancing areas about 20, which is much higher than found of physical-inorganic chemistry is un- with the cobalt catalyst. The reaction is doubtedly the application of phosphine com- believed to involve the five-coordinate plexes of the platinum metals as homo- RhH(CO),(PPh,), as an intermediate. geneous catalysts for hydrogenation and Professor Wilkinson also reported a new, hydroformylation of olefins. In a paper extremely active homogeneous catalyst for presented at the recent symposium on “New olefin hydrogenation: this is the ruthenium Olefin Reactions” at the University of Man- complex RuClH(PPh,),, also a five-co- Chester Institute of Science and Technology, ordinate species. This complex is even more Professor Geoffrey Wilkinson of Imperial active than the rhodium complex RhCl(PPh,), College described recent new work in this but it is selective for a-olefins, as internal field: the reactions he discussed are char- olefins are reduced more slowly by a factor of acterised by a degree of specificity not about a thousand. This specificity is ex- commonly encountered in other catalytic pro- plained by the steric effects of the bulky cesses. triphenylphosphine groups. Unfortunately, Perhaps his most startling disclosure was solutions of the ruthenium complex are very that concerning the rhodium complex trans- sensitive to air and tend to lose activity during RhH(CO)(PPh,), which catalyses the hydro- use. formylation of olefins under ambient con- These disclosures give further proof ditions. With the widely used cobalt catalyst of the power of homogeneous catalysis as a CoH(CO), temperatures of about 100°C and technique for organic reactions, although pressures in excess of IOO atmospheres have many difficult technical problems will need to be used. When cc-olefins are hydro- to be overcome before reactions such as those formylated with the rhodium catalyst, the described find commercial application. ratio of straight- to branch-chain aldehyde is D. E. W. Platinum Metals Rev., 1968, 12, (4) 135 Fourth International Congress on Catalysis ACTIVITY AND SPECIFICITY OF THE PLATINUM mTALS The Fourth International Congress on Catalysis took place in Moscow during the last week in June, and was followed by three specialised Symposia, two of which were also held in Moscow and one in Novosibirsk. This Congress provided, as did its predecessors, a useful forum for the exchange of ideas and experience: an impression of the Congress and a review of the papers relevant to the platinum metals is given in this article. The Fourth International Congress on The purpose of a number of papers was to Catalysis was held at the Moscow State present evidence on how the activity and University, a vast and impressive edifice specificity of a catalytic reaction depended situated in the Lenin Hills in the outskirts of on the nature of the metal employed as Moscow. It was attended by 1,130 active catalyst. C. Horrex, R. B. Moyes and R. C. participants of whom almost two-thirds came Squire (Universities of St Andrews and Hull) from the Soviet Union. Other countries studied the exchange of toluene with deuter- sending major delegations were the United ium over evaporated films and supported States, France, Czechoslovakia, the United metals; large variations were noted in the Kingdom and Holland. relative rates of exchange of the different The theme of the Congress chosen by the kinds of hydrogen atom in the toluene Organising Committee was “Problems con- molecule. R. Merta and V. PoneE (Institute cerning the Prediction of Catalytic Activity”. of Physical Chemistry, Prague) observed that However, within this somewhat unpromising in the hydrogenation of cyclopropane to framework were fitted 86 papers, the majority propane, hydrogenolysis to smaller hydro- of which had a substantial theoretical content carbons occurred on rhodium and certain and were more or less directly pertinent to base metals, but not on palladium and the chosen theme, but a few papers regrettably platinum. The hydrogenation of methylace- contained no new theoretical or experimental tylene over a number of metals was examined work. Plenary lectures were given by Profes- by R. S. Mann and K. C. Khulbe (University sors J. H. de Boer (Holland), s. Z. Roginsky of Ottawa). The hydrogenolysis of cyclo- (U.S.S.R.), D. A. Dowden and C. Kemball hexane over certain of the platinum group (U.K.), G. Rienacker (East Germany, read metals was investigated by 0. V. Bragin and by Dr J. Volter), and Y. Yoneda (Japan). A. L. Liberman (Zelinsky Institute of Organic The first of the three ensuing symposia was Chemistry, Moscow) who found that ruthen- organised by Professor S. Z. Roginsky and ium and osmium were more active than was also held at Moscow State University: its rhodium and iridium. It has long been subject was “Mechanism and Kinetics of recognised that platinum has certain unique Complex Catalytic Reactions”. Twenty-five properties in hydrocarbon reforming pro- papers and a number of plenary lectures were cesses and a further example of its singular given. As certain of the Congress and Sym- behaviour was provided by J. M. Muller and posium papers had close affiliations, it will I;. G. Gault (University of Cam) who showed be convenient to review them together. that of the metals they examined only plati- Platinum Metals Rev., 1968, 12, (4), 136-137 136 num successfully isomerised I,I ,3-trimethyl- compounds and concluded that classical cyclopentane to xylenes. Work of the kind mechanisms can satisfactorily explain most described in this paragraph forms an essential but not quite all the observations. J. Horiuti contribution to the construction of general (Hokkaido University) and T. Keii (Tokyo theories of catalytic action. Institute of Technology) both reported continuations of their previous theoretical Crystallite Size Effects analyses of olefin hydrogenation mechanisms. Five papers on this subject aroused con- siderable interest, as there is a general feeling Old and New Theoretical that we can now talk meaningfully about the Approaches properties of metal crystallites in the KO to Theoretical approaches of various kinds 100 A range. G. C. Bond (Johnson Matthey) loomed large in the proceedings of the Con- presented calculations on the variation in the gress. Predictably the Multiplet Theory of density of edge and corner atoms on regular the late A. A. Balandin frequently featured in cubo-octahedra of increasing size, while contributions from the Soviet Union, and 0. M. Poltorak, V. S. Boronin and A. N. S. L. Kiperman (Zelinsky Institute of Mitrofanova (Moscow University) presented Organic Chemistry, Moscow) attempted to similar calculations based on an octahedral derive the adsorption energies of inter- model and gave evidence to suggest that mediates in a variety of catalytic processes. atoms in planes are sometimes more active The paper by R. A. Gardner (Sohio Labora- than edge or corner atoms. R. van Hardeveld tory, Cleveland) on his Intermedion Theory and F. Hartog (Dutch State Mines) showed was one of the few presenting a relatively new how the density of specific configurations of theoretical approach of some generality. The surface atoms might be estimated through application of Statistical Recognition Theory the infra-red absorption of chemisorbed to catalysis by I. I. Ioffe and his collaborators species; P. C. Aben, J. C. Platteeuw and €3. (Institute of Petrochemical Processes, Lenin- Stouthamer (Shell, Amsterdam) reported grad), and of Information Theory by N. I. that the activity of palladium and platinum Kobozev and B. V. Strachov (Moscow catalysts for benzene hydrogenation was University), is of some general interest. independent of crystallite size to very high degrees of dispersion. Somewhat reluctantly, The Porous Structure of Catalysts workers in this field are coming to the con- The important subject of the proper clusion that “demanding” reactions (i.e. those physical design of catalysts was discussed at sensitive to crystallite size) are the exception the last of the post-Congress Symposia which rather than the rule. was held at Akademgorodok (the Academic Town), near Novosibirsk, an elegant new Mechanisms of Olefin town containing a number of the Research Hydrogenation Institutes of the Siberian branch of the This formally simple catalytic reaction Academy of Sciences. Twenty-seven papers continues to attract both experimental and were presented and discussed, particular theoretical attention. L. Guzci and P. interest being shown in the application of TCtCnyi (Institute of Isotopes, Budapest) Mossbauer and NMR spectroscopy to the studied the reactions of ethylene and propy- study of porous solids. Parts of the dis- lene with tritiated hydrogen over platinum cussion were not improved by tedious pole- black, unfortunately using conditions close mical arguments between specialists, but all to diffusion limitation. G. V. Smith (Southern participants welcomed the opportunity to Illinois University) reported work on the visit Akademgorodok and G. K. Boreskov’s addition of deuterium to a,p-unsaturated impressive Institute of Catalysis. G. C. B. Platinum Metals Rev., 1968, 12, (4) 137 Thermochemistry of the Platinum Metals and their Compounds By w. P. Griffith, A.R.C.S., Ph.D. Department of Chemistry, Imperial College, London The word "thermochemistry" may seem basic solutions. The general arrangement of to have an unduly academic ring to it, far material is very similar to that in Latimer's removed from the world of the experimental well-known book (2)and to anyone acquainted chemist, and indeed in the case of the with that work the present review should platinum metals the information on the cause no difficulties. subject is so widely scattered in the literature For each metal and such compounds for (and often in obscure journals) that it may which data are available the following three seem to have little practical relevance. How- quantities are listed (all refer to the standard ever, when properly handled, such data on the temperature of 298'K): stabilities of the elements and their com- AH'f, the standard heat of formation of the pounds can be helpful to the experimentalist compound from its elements; for they afford a quantitative basis to the AG'f, the free energy of formation of the very fundamental problem of whether a given compounds from their elements; chemical reaction will proceed or not. S", the standard entropies of the elements and The appearance of a comprehensive and their compounds. critical review on the thermochcmistry and The AH", values are obtained from oxidation potentials of the six platinum group calorimetric or vapour pressure data, S" by metals and their compounds is therefore calculation from specific heat or spectro- timely and welcome. This, prepared by R. N. scopic measurements, and AG", from the Goldberg and L. G. Hepler (I) at the equation Carnegie-Mellon University, Pittsburgh, AGf = AH'f - TAS" brings together a mass of previously un- correlated information, more particularly where T=298"K and S is the difference concerned with the aqueous solution chemis- between S" values of the reaction products try of the compounds. It is the purpose of and reactants. this note to indicate the scope of the review, For species in aqueous solution, AGO, the information that it presents and the use values are difficult to measure accurately but that may be made of it. may be obtained by measurements of the For each element there is a brief but well- standard electrode potential E" of the reaction informed discussion of its descriptive chem- under consideration : istry, followed by a table of thermodynamic AG"--nFE"- -23.06nE" data for the metal and its compounds; the approach here is selective and critical, and (where n is the number of electrons involved the authors clearly indicate the value they in the cell reaction and E" the standard attach to the reported results. Each section also oxidation potential, in volts; AG" is then in includes data on oxidation potentials, equil- Kcals/mole). The sign convention used here ibrium constants and related matter, while for E" is (regrettably) not the one recom- oxidation potential diagrams are given for mended by the IUPAC convention but is various metal oxidation states in acidic and in that used in Latimer's book and a number of Platinum Metals Rev., 1968, 12, (4),138-139 138 other texts; e.g. for the cell reaction without a catalyst. Of course, by proceeding to non-standard states of reaction the balance Ag(c)->Ag+(aq)+e- E"= -0.8~. may be changed. It is also possible to All the cell reactions are written as oxidations; calculate equilibrium constants for reactions i.e. with the electrons on the right-hand side. involving the compounds quoted by using The equation these AGOf values together with other readily AGO = - RTlnK= - 1.360 log,,K available data. is also used to calculate AGO for some Potential diagrams are given for the reactions (T=298"K, and K is the equili- various oxidation states of the elements, and brium constant of the reaction). these provide a useful shorthand way of From these data AGO, values are tabulated summarising information on the relative for a number of compounds in the solid and stabilities in solution of their various oxida- (occasionally) gaseous states and for aqueous tion states. solutions. This standard free energy of In short, this review provides at least a formation is the most useful thermodynamic foundation for the more quantitative aspects quantity for practical application; if it is of platinum metal chemistry. It should negative, as in stimulate further research in a field which, for the platinum group elements, has re- Os(c) +z02+ OsO, (g) AG"f= - 70 kcals/mole ceived less attention than it deserves. the reaction should proceed spontaneously in the direction indicated. However, this tells References I R. N. Goldberg and L. C. Hepler, Thermo- us nothing of the rate of such a reaction, chemistry and Oxidation Potentials of the merely that it is thermodynamically possible. Platinum Group Metals and their Compounds, If AGO, were large and positive the reaction Chem. Rev., 1968, 68, 229. z W. M. Latimer, Oxidation Potentials, Prentice could not proceed spontaneously, with or Hall, Second edition, 1959. One Million Ounces of Platinum RUSTENBURG'S INCREASED OUTPUT Since 1964 there has been a fourfold increase in the output of platinum from Rustenburg Platinum Mines, for whom Johnson Matthey are the refiners and distributors. The last big increase was announced a year ago, when ex- tensions to mining and refining operations were put in hand to provide an output of 850,000 ounces of platinum a year. It has now been decided to expand the rate of production to approximately I,OOO,OOO ounces of platinum a year, with of course corres- ponding increases in the supply of rhodium, ruthenium? palladium and iridium. This decision has been made in the light of current assessments of demand during the next five years, notwithstanding the announcement by Universal Oil Products of a new petroleum reforming catalyst that will utilise platinum niore efficiently for a given reforming capacity. This new catalyst will give higher yields, im- proved stability in operation and increased quantities of by-product hydrogen in the widely used Platforming process while it will also help in reducing the amount of contaminants in A new shaft headgear in course of con- high-octane fuels which are contributory to air struction at Rustenburg pollution. Platinum Metals Rev., 1968, 12, (4), 139 Hydrogen in Palladium and its Alloys By F. A. Lewis, Ph.D. Department of Chemistry, The Queen’s University of Belfast A symposium organised by Professor E. Wicke and Professor T. B. Flanagan on the general topic of ‘Hydrogen in Transition Metals’ was held in July at the Institute f iir PhysikaZische Chemie of the University of Munster. Most of the papers presented were concerned with palladium or its alloys and a brief review of these contributions is given here. The bulk of the subject material at this agreement between diffusion coefficients conference concerned the interaction of obtained from several sources and by different hydrogen with palladium and its alloys, techniques over a wide range of temperature. although considerable attention was also paid They also indicated the importance of con- to the nickel/hydrogen system and to the sidering chemical potentials rather than con- behaviour of the hydrides of vanadium, centrations of hydrogen in calculations of niobium and tantalum. diffusion coefficients. Meyer presented an Dr H. Brodowsky of the University of analysis of problems of estimating the Munster opened the symposium with a review kinetics of surface processes in experiments of current attempts to account theoretically in which oxygen and ethylene werc reduced for the form of the (p-c-T) rclationships by hydrogen which was being continuously between the non-stoichiometric hydrogen diffused through a palladium membrane. contents of palladium and palladium alloys F. A. Lewis of Queen’s University, Belfast, and the equilibrium pressure of hydrogen as presented a review of the development of a function of temperature. He outlined the knowledge concerning correlations between theoretical approach in which the non-ideal electrode potential measurements and the solution of hydrogen can be considered as p-c-T relationships of palladium and palla- associated with a combination of lattice strain dium alloys. Attention was given to the deri- and the filling of the electron bands of palla- vation of these relationships from a knowledge dium and its alloys. Dr Brodowsky then of the kinetics of the absorption of molecular discussed the extensions of this form of hydrogen from solution when this was gov- theoretical approach to account for the erned by diffusion transport through the experimental form of low temperature specific Brunner-Nernst interfacial layer. heat data for the palladium/ hydrogen system, Professor T. B. Flanagan of the University and for the form of the p-c-T relationships of of Vermont reviewed the various techniques the vanadium, niobium and tantalum/hydro- which have been employed in electrochemical gen systems. methods for the measurement of coefficients Sustained interest in Munster concerning of diffusion of hydrogen in palladium. He diffusion of hydrogen in palladium was re- next gave a detailed analysis of a technique flected in the contributions of H. Zuchner in current use at Miinster which had an and K. Meyer which dealt, respectively, with important advantage in that there was an diffusion of hydrogen in the high (p-) and effectively negligible flux of hydrogen into or low (w) hydrogen content phases of the out of specimens over the times of measure- palladium/hydrogen system. These talks ments. Professor Flanagan then presented revealed that there is now a high measure of recently determined values of the diffusion Platinum Metals Rev., 1968, 12, (4), 140-141 140 coefficients of hydrogen in several series of in palladium, niobium, vanadium and tanta- palladium alloys as obtained by this tech- lum. This technique seems uniquely valuable nique, and discussed the form of the relation- in indicating favoured crystallographic direc- ships between diffusion coefficient and alloy tions for interstitial jumps. composition. M. Mahnig of the University of Munster Professor B. Baranowski, of the Polish reviewed recent experimental data obtained Academy of Sciences, Warsaw, gave a general at Munster concerning the effect of hydrogen review concerning experimental problems on the magnetic properties of palladium and in the study of the nickel/hydrogen system. several palladium alloys, and on the Moss- An outline was presented of the development bauer spectra of palladium/tin and palladium/ at Warsaw of high pressure apparatus, capable iron alloys. Results were discussed in terms of of attaining pressures up to about 16,000 changes of the electron band structure of atmospheres, which was necessary for study- palladium. ing the form of equilibrium p-c-T relation- Dr H. J. Bauer of the University of Munich ships over a wide range of hydrogen reported extensive experimental information contents. Professor Baranowski then dis- concerning changes of the ferromagnetic cussed measurements of lattice constants, behaviour of thin foils of nickel and nickel/ thermoelectric power and electrical resistance copper alloys on absorption of hydrogen by concerning the nickel/hydrogen systems, and electrolysis. Conjoint measurements had also also presented information concerning mea- been made of changes of the electrical resist- surements of changes of the electrical resist- ance and lattice parameters of the foils. ance of hyrided palladium in equilibrium Photomicrographs of changes of the appear- with hydrogen gas at very high pressures. ance of the nickel foils during electrolysis Professor G. Wedler of the University of were also presented. Erlangen gave a review of experimental studies with ultra-high vacuum techniques of changes of heat of adsorption, electrical re- Hydrogen Diffusion through sistance and work function of evaporated Rhodium-Palladium Alloys nickel films resulting from the adsorption of Palladium alloys used for the purification hydrogen and deuterium. Results from experi- of hydrogen by diffusion must not become ments in which very small amounts of either deformed during the repeated thermal cycles to which they are subjected. Workers at the isotope were successively adsorbed or de- State Scientific Investigation and Planning sorbed, suggested that at all coverages some Institute for the Rare Metal Industry, but not all of either adsorbed isotope was Moscow, have now shown (I) the effect of readily exchangeable. In an analysis in which adding rhodium to stabilise alloys used in the existence of different forms of available diffusion equipment by X-ray structural analyses of I per cent rhodium-palladium, adsorption sites on different crystal faces was I per cent rhodium-19 per cent silver- considered, it was concluded that differences palladium and 10per cent rhodium-palladium. in such respects were not sufficient to have a Deformation of the two I per cent rhodium great influence on the differential heat of alloys after 20 to 800°C thermal cycles was adsorption, in keeping with its observed shown to be due to an CCZP phase change, which altered their volume. 10 per cent behaviour up to complete monolayer coverage. rhodium-palladium, which is nearly as per- Dr R. Rubin, of the European Atomic meable to hydrogen as pure palladium, had Energy Research Centre at Ispra, discussed no phase change, thus explaining its stability the experimental problems in obtaining in such conditions. However, even I per cent diffusion information from measurements rhodium addition significantly increased the stability of 20 per cent silver-palladium. of the coherent scattering of low energy (I) A. A. Rodina, M. A. Gurevich and N. I. neutrons by hydrogen in low concentrations Doronicheva, Zh. jiz. Khim., 1968, 42, (7), 1822. Platinum Metals Rev., 1968, 12, (4), 141-141 141 The First Platinum Refiners THE FRENCH GOLDSMITHS AND THE ARSENIC PROCESS By Donald McDonald Johnson Matthey & Co Limited Credit must undoubtedly be given to the arsenic process of removing base metals from native platinum, and principally to its practice by Jcmety, the Master Goldsmith of Paris, in the years just before and during the French Revolution for leading to thefirst real exploitation of platinum as an industrial metal and for enabling its properties to be fully appreciated. Surprisingly soon after Ulloa’s first an- The early workers soon realised this and nouncement of the occurrence of platinum in knew that they had to get rid of the iron New Granada, samples of the material before they could weld the metal into ingots. reached Western Europe and were examined There were two courses open to them. The exhaustively by a number of scientists there. first was by a dry metallurgical method seek- By 1750 many of its striking properties were ing to extract the iron by a combination of established and thoughts began to turn scorification and fluxing at the highest towards making use of them, but before this temperature possible; the second was by a could be done it was necessary for the granular wet chemical process by which the platinum native metal to be converted into malleable was dissolved in aqua regia and then pre- sheet. cipitated (of course without the iron) by That it was fusible at an extremely high means of potassium or ammonium chloride. temperature was demonstrated by Macquer But this wet process was complex, messy and and Baumk in 1758, although only in a minute slow in developing, and it was not until 1786 quantity in the focus of a powerful burning- that a commercially manageable process mirror. But very early on (BaumC announced emerged from it in Spain. it formally in 1758) the pioneers found that The metallurgists were quicker and were the material could be welded into coherent in the market with a mallcable product at malleable form by forging it at a very high least a year earlier. According to the most temperature, but one well below its melting detailed account of their activities, they point, just as is the case with the working of treated the native metal with three or four iron. times its weight of ‘white arsenic’ (arsenious But with platinum the temperature required acid) and a few ounces of ‘salt of tartar’ or is very much higher than that which is suffi- (later) potassium carbonate. cient for iron and, while attainable, was then The origin of the use of an arsenic com- very difficult to hold. Now unfortunately it so pound as the oxidising agent for the removal happens that the South American native of the iron goes back to the discovery by platinum contains a certain percentage of iron Scheffer in 1751 that the addition of a small and, at these temperatures, this iron oxidises quantity of arsenic to platinum induced it not to the soft oxides of the blacksmith’s to melt at a low temperature. (We know now forge, but to a hard refractory skin of mag- that the platinum-arsenic eutectic contains netite which effectively prevents welding. 13 per cent of the latter and melts at 597°C.) Platinum Metals Rev., 1968, 12, (4), 142-145 142 His successors were preoccupied with this phenomenon, and were confident that some- how it would help them to the solution of their problem. They were right, because in the course of their scorification process the platinum was liquefied in the presence of reduced arsenic and collected at the bottom of the fusion, where it solidified when the melt was allowed to cool. Removal of the Arsenic Their next problem was to remove the arsenic, which they could do by volatilising it either as metal or as oxide, according to whether air was admitted to the process or not. Here they were severely limited as to the temperature to be employed, since on no account must the metal be permitted to melt; if this happened, the free surface would be reduced so much that the process of oxidation and volatilisation would be prolonged almost indefinitely. On the other hand, arsenic oxidises freely at quite a low temperature and the arsenious oxide produced volatilises appreciably at A page from Lavoisier’s report to the Academy in 1790 describing Janety’s process for refining 300°C and freely above 450°C. So if the tem- platinum. In showing two pieces of Janety’s fabri- perature of the mixed metal were kept at cation Laz:oisier emphasised that there was nom no about 500°C and not allowed to approach limit to the type of oeasel that could be produced in platinum the melting point of 597”C, the elimination of the arsenic proceeded at a reasonable The first man to experiment with this speed. Before it was complete, the button complicated process was Franz Karl Achard, was tested carefully for magnetism and, if Professor of Physical Chemistry in the Royal this were still evident, it was crushed to Academy of Science at Berlin, who established powder and the whole process carried out a the principles and latcr poured thc liquid second or even a third time until all trace of arsenic-platinum eutectic into the mould of a magnetism and therefore of iron had gone. crucible (I). But the first commercial interest in the process undoubtedly came from some Forging and Working of the goldsmiths serving the French court, The buttons were next subjected to the who grew up under the conditions of high highest temperature obtainable and then, luxury that applied there in the times of after cooling, cleaned in nitric acid followed Louis XIV and XV. The first to come into by boiling with water until free from acid. the platinum story are Antoine Joseph Tugot Several buttons were then placed one upon and his former apprentice Jacques Daumy, the other, heated to a white heat, struck with a practising at 58 rue de la Verrerie in Paris. pestle to make them adhere, and then forged Hoefer, writing in the article on platinum in thoroughly on an anvil. This produced a the Encyclopedie Moderne, definitely states malleable ingot that could be worked to that these two men were the first to put plati- produce both foil and hammered wire. num to use on a relatively large scale in 1785 Platinum Metals Rev., 1968, 12, (4) 143 (2). Tugot seems to have dropped out, but that he had devoted himself to the work with Daumy carried on the process for several very great obstinacy and courage, that he had years (3) and became a specialist in cladding made many sacrifices and exposed himself to copper with a thin sheet of platinum to form great dangers, but eventually had obtained a doubli metal. success and produced many articles of plat- inum for both artistic and scientific use. The Marc Etienne Janety authors, echoing Lavoisier, point out that, In due course his son succeeded him but it although platinum had actually been ‘melted’ was another whose name ranks highest in the by others before Janety, only small objects history of the exploitation of the arsenic had been made from it; ‘it is therefore to process and that is the King’s Goldsmith, this artist that we owe the bringing of this Marc Etienne Janety. This man, a Master art to perfection and especially the ways of Goldsmith of Paris since 1777, began to take working it on a large scale.’ Full details of an interest in platinum in 1786 (4), and by his process are then given (6). 1788 he is said to have ‘succeeded in making it in large amounts very pure and very The New Metric Standards malleable’ and to have made ‘crucibles, snuff Janety continued his work in Paris until boxes, etc.’ of it. The report goes on: ‘he about 1794 when, deciding that the position makes use of arsenic to melt it but he has of King’s Goldsmith was becoming a little special methods of removing it afterwards . . . incompatible with the political atmosphere very dangerous since he has several times been of the times, he retired to Marseilles to set seen in an atmosphere full of arsenic fumes’. up afresh as a manufacturer of base-metal In I790 he was honoured by Lavoisier clock parts. There, in 1795, he was sought himself introducing to the Academy two out by the new French government, because pieces of his work, one of which was a coffee of his knowledge of the working of platinum, pot with, as Lavoisier was careful to point to come back to Paris and prepare the stan- out, ‘cold-worked parts such as the bottom dards of length and weight for the newly and soldered parts . . . by using together these established metric system. He came back two means there is no limit to what can be to Paris in September 1795 and started work made’ (5). in November. The Commission of Weights In I792 the Academy asked Berthollet and and Measures gave him 200 marcs (say 1600 Pelletier to examine his work to see if it were ounces) of native platinum and agreed to deserving of public support. Their report pay him 15 francs per ounce for the fabrica- was published in the same year and states tion, with an allowance of 25 per cent for One of the standard kilo- grams made by Janety in 1798 in platinum refined by the arsenic process. The label on the case reads ‘Kilogramme Conform6 a la loi du 18 Germinal An 3, presente le 4 Messidor An 7’ Platinum Metals Rev., 1968, 12, (4) 144 The Campo Forniio Medal, struck in platinum in 1798 and showing Napoleon re- turning triumphantly from the wars in Italy anddustria. This niedal required two thousand strokes of the press. indicating considerable hurd- ness, probubly due to the presence of iridium, but also great toughness as a result of eJgieient refining and corn- plete freedom ,from ursenic scrap. Between 1795 and 1802 he made four the loss of his health, of his fortune, of his standard metres and four standard kilograms. profession, that he has succeeded in con- The ha1 products had all to be carefully quering them, and the happy results that he standardised against earlier standards made in has presented to you are without any doubt other metals with different coefficients of the fruit of the greatest and most willing expansion. Eventually this process was com- sacrifice that has been made in the advance- plcted and one of his metres was chosen as ment of an art’ (9). In 1812 d’Arcet reports the approved actual standard and called the again, and he now refers to ‘M. Janetyfils, Metre des Archives. It and its three fellows pupil and successor to his father’, so that are still preserved in Paris (7). we can assume that the latter retired about In 1798 a platinum medal commemorating this time. The objects presented by the son the Treaty of Campo Formio was struck in on this occasion were even larger vessels of Paris to a design of the famous medallist 22 and 16 litres for the concentration of sul- Benjamin Duvivier and presented to the phuric acid, but in the same report we learn Institut. It is still in existence and was shown that ‘M. Janety announces that for more than in 1953 in London at the Wollaston Exhibi- a year he has ceased to use arsenic in the tion. The metal has taken the design per- preparation of his platinum’ (10). fectly, but there is a fine crack visible on the reverse. It is said to have required two References thousand blows of the fly-press, which in- I F. K. Achard, Nouveaux Mimoires de I’Acad- dicates considerable hardness, no doubt due emie Royale des Sciences, Berlin, 1781, 12, to the presence in the metal of iridium, but 107-9; Chemiscke Annalen von D. Lorenz Crell, 1784, I, 3-5 at the same time great toughness as a result of 2 J. C. F. Hoefer, Encyclopedie Moderne, 1850, efficient refining and complete freedom from 23, 822-824 arsenic (8). 3 J. Ingenhousz, Nouvelles Experiences et Observations sur Divers Objets de Physique. In 1810 Janety exhibited a bucket-shaped paris: 1785-r789, 2, 505-517 vessel, seven inches in diameter and five 4 B. Pelletier, Observations sur la Physique inches deep weighing eighteen ounces and a (Rozier)~ 34, ‘97 5 A. Lavoisier, Andes de Chimie, 1790, 5, 140 retort holding a litre, showing that the size 6 C. L. Berthollet and B. Pelletier, AnnaZes de and scope of his work was increasing. The Chimie, 1792, 14, 20-33 chemist d’Arcet in introducing these says: 7 C. Wolf, Annales de Chimie et de Physique, ‘You know with what perseverance M. Janety 1882, 25, 66 8 Vever, Histoire de la Bzjouterie frangaise au pdre has struggled for more than thirty-three XIX’e Siicle, 119-120 years against the obstacles opposing the 9 J. P. d’Arcet, Bulletin de la Socie‘ti d’En- reduction of native platinum into malleable couragement pour l’lndustrie, 1810, 9, 54-57 10 J. P. d‘Arcet, Bulletin de la Socie‘ti d’En- Platinum- It is Only by long labours and by couragement pour l’lndustrie, 1812,11,207-208 Platinum Metals Rev., 1968, 12, (4) 145 ABSTRACTS of current literature on the platinum metals and their alloys PROPERTIES The Electrical Resistivity of Palladium- Hydrogen and Palladium-Deuterium Alloys Young's Modulus of Single Crystals of between 4 and 300°K Palladium at High Temperatures N. s. HO and F. D. MANCHESTER, Can. J. Phys., H. MASUMOTO, H. SAITO and S. KADOwAKI,J.Jaj?an 1968,46, (111, 1341-r345 Inst. Metals, 1968, 32, (6), 529-532 Electrical resistivity measurements at 4-300"K, Measurements at 0-600°C using a dilatometer and 0-0.62 H;Pd, showed that an anomaly exists and a vibrator-controlled oscillator system in the resistivity of Pd-D as well as that in Pd-H. showed that the Young's moduli of a Pd single crystalare7.3~~13.77and 19.44~IO~ kg/cm'at 2o'C The Reaction of Hydrogen with Palladium- inthe Platinum Metals Rev., 1968, 12, (4), 146-154 146 fracture of Ir showed that, except where macro- The Effect of Ruthenium, Rhodium and scopic imperfections occur, cracks can be nu- Palladium on the Heat of Expansion of Iron- cleated only after extensive work-hardening. Nickel and Iron-Nickel-CobaltAlloys Plastic relaxation of the crack is inhibited because N. A. SOLOV'EVA, M. I. YUDKEVICH, I. I. PASTERNAK impurities substantially increase the critical re- and v. z. POGOSOV, Metalloved. Term. Obrabat. solved shear stress. Thus brittle fracture in Ir Metal., 1968, (41, 45-46 is caused mainly by impurities. Additions of Ru or Kh to Fe-Ni and to Fe-Ni-Co alloys raised their coefficients of thermal expansion Reactions of Uranium with the Platinide but had no effect on their Curie points. Additions Elements. I. The Uranium-Ruthenium of 5":) or 2o:,Pd to Fe-Ni-Co at the expense of System Fe and Ni raised both factors but the more in- J. J. PARK, J. Res. NBS, Sect. A, Phys. Chem., tensive rise occurred for the coefficient of thermal 1968, 72A, (I), 1-10 expansion, which rose 5.ox 10-' deg at 20- Thermal analysis, metallography and X-ray diff- 700°C. raction revealed five intermetallic compounds : U,Ru, formed peritectically at w 937'C; "URu," melting congruently at w 1158°C; U3Ru4,formed CHEMICAL COMPOUNDS peritectically at w r163"C; U,Ru,, formed peri- tectically at w 1182°C; URu,, formed peritectic- Complex Sulphates of the PIatinum Metals ally at w 1850°C. "URu" undergoes solid-state s. I. GINZBURG and N. N. CHALISOVA, Zh. nearg. transition at w 795°C. Eutectics occur at w 886'C, Khim., 1968, 13, (s), 1239-1244 18.5 at.:/; Ru and x1148"C, 49 at.'!,;, Ru. A review of the electrochemical and other proper- Maximum solid solubilities are w7.5 at.:4, Ru in ties of the Pt metal sulphates. (46 references.) U, and w r.3 at.% U in Ru. Ru lowers the y-U transformation to w691"C, and the /3-U trans- High Pressure Synthesis of Pyrochlore-type formation to % 625°C. Oxides of Tetravalent Platinum 11. The Uranium-RhodiumSystem H. R. HOEKSTRA, s. SIEGEL and F. GALLAGHER, Ibid., 11-17 Abstr. Papers, rjjth Mtg, Am. Chem. Sac., 1968, Similar studies revealed four intermetallic com- (Mar.), M76 pounds: U,Rh,, formed peritectically at w I 155°C Fifteen A,lllPtlv,O, pyrochlore oxides, where with a solid state transformation at x720'C; A-Sc,In,Y, or rare earth, synthesised from U,Rh,, formed peritectically at w 1450°C; binary oxides at 30-50 kbar, 100-1500'C, possess U3Rh,, formed peritectically at w 1550°C; URh,, cell parameters 9.85-10.42A and are stable to melting congruently at x 1700'C. Eutectics w IOOO"Cat ambient pressure. occur at x 865"C, 24.5 at.".;, Rh and w 13g3"C, 87 at.?; Rh. Maximum solid solubility of Rh in Synthesis and Properties of Two New U is w 8 at.%, and of U in Rh is % 3 at.%. Members of the Ride Family Rho, and 111. The Uranium-Iridium System PtO, J. J. PARK and L. R. MULLER, Ibid., r9-25 R. D. SHANNON, Solid state Commun., 1968, 6, (3), Similar studies revealed five intermetallic com- 139-143 pounds : UJr formed peritectically at w 945°C A tetragonal rutile form of Rho, and an ortho- and decomposing eutectoidally at w 758°C; rhombic distorted form of PtO, were made from U31r,, formed peritectically at % 1121°C; UIr, commercial oxides at 700"C, 3000 atm. These melting congruently at Z 1470°C; UIr2, formed compounds have room-temperature resistivities peritectically above 1850°C; UIr, with congruent Platinum Metals Rev., 1968, 12, (4) 147 of pOg at 453-723”c enabled new values of cations suppressing atomisation of H,. Activation H’f,298, F’f,,,, and Cp for oxides of Ru to be of H, was mainly by formation of Pt-H, dipoles, recommended. It is suggested that during calcin- it was assumed. ing of nuclear waste there is volatilisation of Ru as RuO, and also as either nonequilibrium con- On the Activity of Platinum Catalysts in centrations of RuO,(g), very fine particles, or as Solution. 111. Facets on Flame-formed another Ru vapour species. Platinum Spheres T. B. WARNER, J. Electrochem. SOC.,1968, 112, (6), The Oxidising Properties of the Third 615-616 Transition Series Hexafluorides and Related Pt beads melted with an oxyhydrogen flame and Compounds cooled slowly develop flat regions corresponding N. BARTLETT, Angew. Chem. internat. Ed. En., to {rIr} and {roo} crystal faces, which increase 1968, 7, (61, 433-439 catalytic activity. Electron affinity E increases regularly by 20 kcal/ mole for each unit increase in atomic number over Surface Oxidation and Reduction of Platinum the series WF, < ReF, < OsF, < IrF, < PtF,, Electrodes: Coverage, Kinetic and Hysteresis while affinity for F- decreases. PtF,, (E,, -156 Studies kcal:mole), oxidises 0, and Xe. IrF, is more D. GILROY and B. E. CONWAY, Can. J. Chem., 1968, effective in oxidative fluorination of ONF to 46, (61, 875-890 ONF,. Polarisation and hysteresis effects were used to study the nature and extent of surface oxidation on three sorts of Pt surface. The quantity of ELECTROCHEMISTRY reducible oxide depends on potential and time of Mechanism of Electrolytic Perchlorate anodic polarisation. Galvanostatic and potential Production sweep techniques were compared. M. P. GROTHEER and E. H. COOK, Electrochem. Technol., 1968, 6, (5-6), 221-224 Adsorption and Oxidation of Carbon Mon- Smooth bright Pt is the most efficient anode for oxide on Platinised Platinurn Electrodes the electrochemical oxidation of NaC10,. The M. W. BREITER, J. phys. Chem., 1968, 72, (4), effects of current density, NaCIO, concentration 1305-13 13 and anode polarisation on perchlorate production Anodic oxidation mechanisms of the two types of are analysed and a mechanism is suggested where- CO adsorbed on platinised Pt at open circuit are by d(C10,-)/dt, the rate of production, is equal to discussed. Saturation coverage of H atoms K,(ClO,-)i, where K, is proportional to the true decreases linearly with CO coverage and the H- current density and (ClO,-ji is the concentration adsorption isotherms change. of chlorate ion at the anode surface. Interactions of Adsorbed Organic Layers ElectrochemicalDetermination of the Specific with Hydrogen Atoms on Platinum Elec- Surface and the Activity of Porous Platinum trodes S. B. BRUMMER and K. CAHILL,US Rept AD 663,903, H. BINDER, A. KOHLING, K. METZELTHIN, G. SANDSTEDE and M.-L SCHRECKER, Chem.-Ing.- Tech., 1968, (Jan.), 28 PP 1968, 4% (121, 586-591 Studies in I M H,SO, at 40°C of H atom coverage The specific surface area of Raney Pt depends on of smooth Pt foils indicate that the presence of A1 content and decreases with use. Results were CO leads to repulsive H-CO interaction at all obtained from measurements of cathodic adsorp- potentials in terms of sites occupied and at tion and anodic desorption of H atoms by poten- >O.I~V versus R.H.E. Interaction of H-CO, is tiostatic sweep methods and were compared with repulsive above 0.20 V but attractive below 0.20 those obtained from BET surface area measure- V. Results are discussed. The cathodic method of H-atom charging for estimating organic coverage ments. on Pt seems least suspect. Interactions with H on The Effect of Surface-active Cations on the Pt show that the species CO,,, and “reduced CO,” are different. Catalytic Activity and Selectivity of Pt Black M. TOKTABAEVA, G. D. and D. v. F. ZAKUMBAEVA On the Activity of Platinum Catalysts in SOKOL’SKII, Kinet. Kataliz, 1968, (3), 690-692 9, Solution. Part I. Effects of Thermal Treat- Studies at 20 and 30°C showed that increasing concentrations of the surface-active cations Cd, ment and Chemical Etching on the Pt-O/ Zn, Pb, Sn, In, TI, Mn, and Re decreased the Hydrogen Specific Reaction Rate rate of hydrogenation of propargyl alcohol on Pt T. B. WARNER, s. SCHULDXNER and B. J. PIERSMA, black. A decrease in selectivity for the hydro- US Rept AD 664,490, NRL Rept 6622, r967, genation of triple bonds was connected with the (Dec.1, IX PP changed mechanism due to certain adsorbed This reaction is very sensitive to pretreatment of Platinum Metals Rev., 1968, 12, (4) 148 the Pt and is a responsive test for cleanliness of and the stability of the complex formed between electrode and electrolyte. H was present in passive film cations and solution anions. An electrochemically clean I M H,SO, and in the immersion deposit of Pt or another Pt metal derma of the Pt. Reaction of H with Pt-0 on Pt inhibits cathodic reduction of the passive film, SO beads was usually faster where their heating to protecting recessed areas from etching, and in- m.p. had been more uniform and their re- creasing the range of hard Cr plating by giving crystallisation on cooling had been slower. The high-speed, smoother harder deposits. specific rate of chemical reaction of chemisorbed Part 11. A New Stop-off Procedure 0, with H was lower on Pt wires than on Pt beads, Ibid., 246-249 due to differences of crystallite size and drawing The surface to be stopped off is coated with an defects, but results on both were variable. immersion deposit of a low H, overvoltage noble metal such as Pt or Pd. This procedure prevents Oxygen Overvoltage on Bright Rhodium plating where not desired and yet gives uniform J. P. HOARE, Electrochim. Acta, 1968, 13, (3), 417- hard Cr deposits with smooth, rounded edges, 42 8 which can be put in service with no further Anodic evolution and cathodic reduction of 0, on finishing. bright Rh electrodes were studied galvano- statically and by potentiometry. 0, is absorbed Platinised Titanium Anodes Permit Plating above 1400°C: to give Rh,O,, which produces a of “Unplatable??Parts higher overvoltage than do Pt electrodes. Rh has E. JOLLIFF, Plating, 1968, 55, (5), 508 a poor surface for decomposition of H,O,. Auxiliary anodes of Pt/Ti enabled awkward angles of wheel covers to be Ni- and Cr-plated. Their Oxygen Oven-oltage on Bright Iridium life is more than 100 times that of a similar design J. P. HOME, J. electroanal, Chem. interfac. Electro- in Ni. chem., 1968, 18, (3), 251-259 Galvanostatic and potentiostatic studies of bright Electrodeposition of Ductile Palladium Ir beadelectrodes in 0,-saturated H,SO, indicated J. M. STEVENS, Trans. Inst. Metal Finish., 1968, that the 0,-reduction mechanisms on Ir and Pt 46, (11, 26-31 cathodes are similar. Although IrO, is formed, the An electrolyte based on [Pd(NH,),]Brz can be 0 ,-evolution mechanism is that of H,O-discharge. used under a range of conditions to provide Pd The adsorbed 0, layers on Ir are believed to be coatings with up to zo:i, ductility. Under the good electronic conductors. Adsorbed 0, on Ir preferred conditions for vat plating the cathode cathodes hinders reduction of 0, to H,O, but efficiency is >9o?;, and the rate of deposition is promotes reduction of H,O, to Hz. Intermediate IEL/min. Regeneration of the electrolyte is simple H,O,, which is stable, forms during the 0,- and incorporates purification. Impurity effects reduction process. and wear characteristics are studied. Electrooxidation of Methanol on Pt -1-Ru and The Corrosion Resistance of Electroplated Ru Electrodes at Various Temperatures Rhodium Deposits on Nickel v. s. ENTINA and 0. A. PETRII, Elektrokhimiya, K.-E. BECKER, H. SCHLEGEL and A. KUBAT, Metall- 1968, 4, (6), 678-681 oberfEiiche, 1968, 22, (S), 145-153 Stationary polarisation curves were obtained for Measurements of corrosion current density and the electrooxidation of CH,OH on Ru, platinised of current density-potential curves for Ni and Rh Pt, 10 and 255; Pt-Ru, and 10, 25 and 40‘;; show that contact corrosion in the pores of electro- Ru-Pt electrodes in ZN H,SO,+zM CH,OH at plated Rh deposits on Ni is determined by reac- various fixed temperatures. Products were tions on the Rh. Corrosion is accelerated at low analysed for HCHO, HCOOH and CO,. pH but is still detectable at pH9. This indicates that the standard Rh electrodeposit on Ni may not stand up to such severe conditions as are met ELECTRODEPOSITION AND with in the food industry. SURFACE COATINGS High-speed Hard Chromium Plating. Part I. LABORATORY APPARATUS Etch-free Plating AND TECHNIQUE R. D. BEDI, Plating, 1968, 55, (3), 238-246 Etching frequently occurs while hard Cr plating Initial Field Evaporation of Platinum Sur- steel or steel alloys from fluoride-catalysed baths faces in the Field Ion Microscope at unprotected low current density areas, thus c. A. SPEICHER and w. T. PIMBLEY, Surface Sci., contaminating the bath. It is due to homogeneous 1968, 10, (31, 47*473 electrochemical corrosion, depending on the Two methods of obtaining atomically smooth Pt passivating properties of the electrolyte, the tip surfaces are described. Rough surfaces result- degree of cathodic activation of the passive film, ing from etching may be treated by field evapora- Platinum Metals Rev., 1968, 12, (4) 149 tion at 78°K or by field evaporation at 10°K while n-paraffins was greater than with IO(~(~fluoride or stress cycling the tip. no fluoride at 300 psig HB. Effects of pH2,type of A1,0,, S compounds, N compounds, and Versatile and Rapid Trace Nitrogen Analysis aromatic compounds were studied. Reduced of Petroleum Materials by Microcoulometry pH2from 1000 to 50 psig increased isomerisation D. R. RHODES, J. R. HOPKINS and J. c. GUFPY, Abstr. from 37 to 88%. Papers, JjjthMtg, Am. Chem. Soc., 1968, (Mar.), R37 Dehydrocyclisation of 2 -n-Butylnaphthalene 10 to 20 times the sensitivity of the Dohrmann N, on Alumina-Platinum Catalyst analyser was obtained by modifications, including L. A. ERIVANSKAYA, G. A. SHEVTSOYA, N. L. the use of Pd instead of Pt pH-sensing electrodes. KOMISSAROVA and A. F. PLATE, Neftekhimiya, 1968, The range was extended to 0.1~0.02 ppm, 8, (2), 192-197 600'C with is0: reproducibility. Studies of the effects of temperature, volume rate, test duration and concentration of Pt in Pt;Al,03 Production of Ruthenium Targets [Foils] catalyst during C,-dehydrocyclisation of 2-n- for Nuclear Research and a Study of butylnaphthalcne showed that the phenanthrene : Ruthenium, Rhodium, and Palladium anthracene product ratio depends on the reaction Deposits temperature. The reaction is accompanied by c. N. MEDYANIK and L. I. KADANER, Ukr. fiz. Zh., cracking, by isomerisation and by dehydrogena- tion of alkyl groups. The chief mechanism leading 1968, 13, (11, 127-129 Electrolytic production of Ru foils is to the predominant formation of phenanthrene at 3~ 4oo-51o"C is the intermediate formation of described. The dependence of the internal stress a-(buten- I-y1)naphthalene. of Ru, Rh and Pd foils on electrolyte concentra- tion and current density was studied. The Surface Transport of Various Gases on a Platinum-Alumina Catalyst BRAZING D. GELBIN, Chem. engng SCi., 1968,23, (I), 41-49 Permeation measurements of the surface trans- Joining Dissimilar Metals by Gas Tungsten- port rates of C,H,, n-C,H,,, n-C,H,, and Kr in Arc Braze-Welding a Pt,'Al,O, pellet showed that surface transport D. E. SOLOMON, WeEdingJ., 1968, 47, (3), 181-191 of hydrocarbons is related to the dissociative Brazing alloys for the tungsten arc technique of adsorption of the migrating gas. Surface mobility joining dissimilar metals were evaluated by tests decreases with increasing molecular length. on welding an annular disc around a pipe. The Activation energies, which increase from C,H, to eutectic alloys Pd-Au, m.p. 1r9o"C and Pd-Co, C,H,,, are rather larger than the corresponding m.p. 1220°C were used successfully in a number heats of adsorption. The behaviour of Kr is of cases, e.g. Pd-Au : discs of carbon steel to different and a mechanism for it is proposed. stainless steelpipe,Ni-Fe-Co alloy to stainless steel, stainless steel to carbon steel, Mo, Ni-Fe-Co, and On the Role of C,-Dehydrocyclisation in the W; Pd-Co: discs of carbon steel to carbon steel Aromatisation of n-Paraffins in the Presence and Ni-Fe-Co pipes, Ni-Fe-Co to carbon steel of Platinum on Alumina Catalysts and Ni-Fe-Co, stainless steel to Mo, stainless YU. v. FOMICHEV, I, v. GOSTUNSKAYA and B. A. steel and W. KAZANSKII, Izv. Akad. Nauk SSSR, Ser. Khim., 1968, (5), 1112-1117 HETEROGENEOUS CATALYSTS Microreactor studies of the aromatisation of n-C,H,, and of n-C,H,, over 0.6 Platinum Metals Rev., 1968, 12, (4) 150 the respective aromatic compounds, as well as by pC,H,2increases, the order of the reaction with C,-dehydocyclisation with subsequent dehydro- respect to CGH,, changed from first to zero isomerisation. order. Increasing pHr retards the reaction. Apparent activation energy was 32 kcal,/mole. Competitive Hydrogenations on Platinum A. s. HUSSEY, R. H. BAKER and G. w. KEULKS, J. Dehydrocyclisation of n-Hexane on Catalysis, 1968, 10, (3), 258-265 Palladised Tape Results of competitive hydrogenations of 14 pair V. M. GRYAZNOV, K. MALDONADO, E. KHAZHZHAR combinations of 10 cycloalkenes from solution in and D.-K. OLUOCH OKEI0,Kinet. Kataliz, 1968, 9, cycloalkane solvents on 0.52:b Pt/Al,O, at 25"C, (21, 435-437 I atm agreed with both equilibrium and rate- Mass-spectrometric studies of n-C,H,, vapour controlled chemisorption models, the latter being conversion on palladised tape at x IO@ mm Hg preferred. Stereochemical and product ratio indicated slight dehydrocyclisation at ZOT, problems are discussed and factors affecting intensifying with increased temperature. At 20o'C chemisorption of cycloalkenes on Pt surfaces are there is almost complete conversion into C,H,. considered. Palladium Areas in Supported Catalysts. Catalytic Dehydrogenation of Cyclohexane : Determination of Palladium Surface Areas a Transport-controlled Model in Supported Catalysts by Means of Hydrogen R. R. GRAHAM, F. C. VIDAURRI and A. J. GULLY, Chemisorption AZChE J.9 1968, 14, (311 473-479 P. c. ABEN,~.Catalysis, 1968, 10, (3), 224-229 Kinetics of the dehydrogenation of cyclohexane Hydrogen chemisorption proved suitable for with excess H, over Pt/Al,O, at ~oo-~oo"(~,zI-~Idetermination of Pd surface areas in Pd:Al,O, atm and at Reynold's numbers 20-65 indicate a and Pd/SiO, when the chemisorption conditions rapid overall reaction influenced by external con- were chosen carefully. It was also suitable for centration, temperature gradient and reverse particle size determination in cases where inter- reaction. ference by the support caused other methods to fail. Combined surface area and H, chemisorption The State of Platinum in Promoted Platinum measurements on Pd black showed that I H atom Catalysts and the Nature of the Activity of was adsorbed on each exposed Pd atom, as con- Metallic Catalysts in the Dehydrocyclisation firmed by electron microscopy, of Paraffin Hydrocarbons N. R. BURSIAN, s. B. KOGAN and z. A. DAWDOVA, Heterogeneous Catalysis by Metal Chelates - Kinet. Kataliz, 1968, 9, (3), 661-667 Isomerisation of Butenes Additions of Li, Na and Cs to Pt/AI,O, and M. MISONO, Y. SMTO and Y. YONEDA, Zbid., (2), Pt/SiO, promote the catalysts by stabilising the 200-202 active centres containing Pt ions both in air and [Pd(acac),] mounted on silica gel is an efficient H,. A suggested model contains complex active catalyst for isomerisation of C,H,. Rate constant centres incorporating Pt4+ions. Its action during at 61.5% for cis-2-C4H, isomerisation was dehydrocyclisation of paraffins is discussed. 4.3 x ~o-~g-lmin-l,far higher than with Ni or Pt as the central metal ion and also far higher than with Hydrogenation of Ethylene on Platinised dmg as chelate. Silica Gel On the Mechanism of 1-Butene Isomerisation I. NICOLAU, Rev. roumaine Chim., r968, 13, (I), on Supported Palladium 71-75 s. CARRA and v. RAGAINI, Zbid., (3), 230-237 The rate of hydrogenation of C,H, on 0.1~:~ Studies of double-bond migration of I-butene on Pt/SiO, at 30-9OCc, I atm is dependent on H, concentration but is independent of C,H4 con- 0.484% Pd,'Al,O, in the absence of H2indicated centration. An apparent activation energy of stereoselectivity towards cis-2-butene. Kinetic 4.2 kcal/mole is reported. studies by both integral and differential reactor techniques at 160-240°C suggested two mechan- isms for isomerisation: the former with two atomic Kinetics of Isomerisation of Cyclohexane on centres and stereospecific towards cis isomer; the Pt Zeolite Catalyst in a Gradientless System latter tending towards equilibrium of trans- and under Pressure of Hydrogen cis-2-butene. u. M. KURKCHI, v. I. GARANIN and KH. M. MINACHEV, Kinet. Kataliz, 1968, 9, (3, 571-576 The Hydroisomerisation of n-Butenes. 1. The rate of isomerisation of C,H,, on a Pt The Reaction of 1-Butene over Alumina- and zeolite catalyst was studied in relation to the size Silica-supported Rhodium Catalysts of the catalyst granules, the rate of circulation of J. I. MACNAB and G. WEBB,J. Catalysis, 1968, 10, the gas mixture, and the temperature and partial (I), 19-26 pressure of C,H,, and H,. At 288-318"C, as Studies of the reaction of I-C,H, with H, over Platinum Metals Rev., 1968, 12, (4) 151 5"/oRh/Al,0s or s;/,Rh,'SiO, at -20 to +SOT and H, over pumice-supported catalysts in a gave the kinetics and apparent activation energies static system showed that the initial rates of for hydrogenation and isomerisation. The initial reaction depended only on the initial pH2,except cis :trans ratio in 2-C4H, is greater than the for Pt/pumice where the pressure of methyl- thermodynamic equilibrium value but it de- acetylene was also important. Apparent activa- creases with increasing temperature. The support tion energies for pumice-supported Fe, Co, Ni, has little effect. A suggested isomerisation Rh, Pd, Ir, and Pt were 14, 13.3, 16.8, 8.6, 10.3, mechanism is via a 1-methyl-x-ally1 intermediate. 9.2, and 12.9 kcal/mole respectively and the activities were in order Pt >Pd >Ni >Ir > Rh> Catalytic Activity of Rhodium and Ruthenium Co:>Fe>Ru, 0s. in the Hydrogenolysis of Ethane G. K. STAROSTENKO, T. A. SLOVOKHOTOVA, A. A. Consecutive Hydrogenation of Double Bonds BALANDIN and K. A. EL KHATTIB, Vest. Moskov. of Cycloheptatriene over Palladium, Univ., Ser. IZ, Khim., 1968, (2), 52-55 Platinum and Rhodium Catalysts Activities of Rh/SiO, for hydrogenolysis of B. D. POLKOVNIKOV, 0. M. NEFEDOV, E. P. MIKOS and C,H, were measured at 155-190"C and activation N. N. NOVITSKAYA, zzv. Akad. Nauk SSSR, ser. energies were calculated for various H,/C,H, Khim., 1968, (6), 1240-1245 mixtures. Hydrogenation of conjugated double bonds of cycloheptatriene-1~3,s proceeded consecutively Modification of Raney Catalysts by Addition on borided Pd catalyst, with less selectivity on of Transition Metals. VIII. Electrooxidation borided Rh, and with no selectivity on borided Pt. Consecutive hydrogenation of unsaturated of Hydrogen and Catalytic Hydrogenation on bonds of cycloheptadiene-1,3 also occurred on Raney Nickel-Ruthenium Alloys borided Pd catalyst. A. B. FASMAN, A. ISABEKOV and B. K. ALMASHEV, Zh. $2. Khim., 1968, 42, (4), 903-908 HOMOGENEOUS CATALYSIS Studies of the effect of the composition of Raney Ni-Ru catalysts on the kinetics of hydrogenations Organic Syntheses by Means of Noble Metal of potassium maleate, o-nitrophenol, and DL- Compounds. XXXVI. Reactions of Car- naphthoquinone, and of anodic oxidations of H, banions with Cyclooctadienepalladium and and alkaline electrolytes showed that new phases were formed in the initial Ni-Ru-A1 alloys and -platinum Halide Complexes and Tetra- that the Ru addition leads to growth of the crystal phenylcyclobutadienepalladium chloride lattice parameters of Raney Ni. Complex H. TAKAHASHI and J. TSUJI, J. Am. Chem. Soc., Structures of Olefins and their Simultaneous 1968, 90, (91, 2387-2392 Hydrogenation on Ru Catalyst Studies of C-C bonding by the reaction of diene- palladium and -platinum halide complexes with L.KH. FREIDLIN, E. F. LITVIN and s. K. TILYAEV, carbanions showed that malonate and aceto- Neftekhimiya, 1968, 8, (2), 155-161 acetate react smoothly at room temperature with Studies with su0Ru'C show that it possesses cyclooctadienepalladium and -platinum com- high selectivity during simultaneous hydrogena- plexes to give new complexes with B and x bonds tion of olefins with various structures. The H, with metals. Reaction of these with methyl- is added in positions depending on the alkyl sulphinyl carbanion produced bicyclo[6.1.0]- groups to be substituted, the structures and the nonene derivatives. Malonate attacked the com- position of the double bonds. plexes to give 2,6-disubstituted bicyclo[3.3.0]- octane rings. Stereoisomeric Conversion of Individual cis- and trans-3-Methylpentene-2 in the Pres- Palladium-catalysedReactions of Unsatura- ence of Group VIJI Metals ted Compounds in Non-aqueous Solvents M. ABUBAKER, 2. S. KHRUSTOVA, I. V. GOSTUNSKAYA c. F. KOHLL and R. VAN HELDEN, Rec. Trav. chim. and B. A. KAZANSKII, Vest. Moskov. Univ., Ser. ZI, Pays-bas, 1968, 87, (5), 481-500 Khim., 1968, (2), 148-152 The formation of vinyl acetate is first order in The activity and selectivity of C-supported catalyst and in acetate concentration. Acetate is catalysts for cis-, trans-isomerisation of cis- and thought to displace chloride via a x-olefin-Pd(I1) tram-3-methylpentene-z are in the order Pd> complex. Effects of chloride ion, solvent and Rh>Ru>Os> Ir>Pt. various transition metal salts are discussed. Catalytic Hydrogenation of Methylacetylene Polymerisation of AUene with a Soluble over Group VIII Metals Palladium Catalyst R. S. MA" and S. C. NMK, ZndianJ. TechnoL, 1968, e. D. SHIER, Abstr. Papers, Ij 5th Mtg, Am. Chem. 6, (z), 57-58 SOC.,r968, (Mar.), T25 Studies of the reaction between methylacetylene 1 : I mole ratio of Pd(N0,)2 : triarylphosphine in Platinum Metals Rev., 1968, 12, (4) 152 glacial CH,COOH catalysed head-to-head poly- FUEL CELLS merisation of allene. Chemical and spectral tests indicated that the polymer contained repeating Activation of Nickel Fuel Electrodes with conjugated diene units. Platinum Catalysts D. M. DRAZIC, A. R. DESPIC and N. n. KOSELJ, The Dimerisation of Butadiene by Palladium Electrochem. Tecknol., 1968, 6, (3-4), 98-100 Complex Catalysts The activity of porous Ni fuel cell electrodes, s. TAKAHASHI, T. SHIBANO and N. HAGIHARA, Bull. activated by chemical plating with a solution of Chem. SQC.Japan, 1968, 41, (2), 454-460 H,PtCl,, Pb(CH,COO), and NaCI, depended on Pd(Ph,P),(C,H,O,) catalysed linear dimerisation the concentrations of Pt and of the neutral salt, of butadiene to form 1,3,7-oaatriene in aprotic on the flow rate of the solution through the elec- solvents and r-alkoxy-z,7-octadiene and/or trode, and on the amount of Pt deposited. With 1,3,7-octatriene in alcohols, depending on the I mg Pt/cmz, IOO mA/cm2 the best H, electrodes nature of the solvent. Dimerisation in C,H,OH, had overpotential 6smV. It appears from Pt CH,COOH or amines produced solvent-dimer distribution measurements that, whatever the adducts. overall electrode thickness, the active layer is ko.3 mm. Carbonylation of Olefins under Mild Tem- perature Conditions in the Presence of Electrocatalysts for Hydrogen/Carbon Mon- Palladium Complexes oxide Fuel Cell Anodes. 111. The Behaviour K. BITTLER, N. YON KUTEPOW-, D. XEUBAUER and of Supported Binary Noble Metals H. REIS, Angew. Chem. intmnat. Ed. En., 1968, 7, D. w. MCKEE and A. J. SCARPELLINO, Electrochem. (51, 329-335 Tecknol., 1968, 6, (3-4), 101-105 L,PdX, complexes, (where L is a ligand such Practical CO-tolerant anode electrocatalysts were as phosphine, nitrile, amine, or olefin; where X is prepared from Pt and Ru on inert substrates such acid; where m+n-3 or 4) are efficient catalysts as B,C. Catalyst activity depends strongly on the for both ester and acid production below IOO‘C. preparation and composition of the metal phase. Polyunsaturated olefins were carbonylated selec- Using reformer gas as fuel with up to 1o”i:CO at tively. 85”C, satisfactory results were obtained with as little as 3 mg/cm2 metal in 5N H,SO,. The high Transition Metal Catalysis Exemplified by performance of Rh-Pt or of Ir-Pt blacks is largely Some Rhodium-promoted Reactions of lost when these are supported, perhaps because Olefins the mechanism of anodic oxidation is different. R. CRAMER, Accounts chem. Res., 1968, I, (6), 186-191 The Rh ion catalysed syntheses C,H,+C,H,, CATHODIC PROTECTION CzH4+ CIHl +1,4-C6H1,,, 1-C,H8 + isomeric linear C,H8, and the effect of thermodynamic or Internal Cathodic Protection of Salt Water kinetic control on the products are discussed. Co- Pipelines with the Aid of Platinised Titanium ordination of Rh with the reactant molecules Anodes causes orientation and reduces energy barriers to J. w. KUHN VON BURGSDORFF, Werkstofle Korrosion, the reaction. 1968, 19, (61, 473-478 Continuous partly platinised Ti wire anodes were Dimerisation of Acrylonitrile by Ruthenium used to protect long pipelines. A current density Chloride of ~15omA,/m~was required but could be A. MISONO, Y. UCHIDA, M. HIDAI, H. SHINOHARA and reduced considerably by coating the pipeline Y. WATANABE, Bull. Ckem. SOC.Japan, 1968, 41, with a passive protective coating. (2), 396-401 RuC1,.3H,O under H, atmosphere catalysed the formation of cis- and trans-1,4-dicyano-1-butene CHEMICAL TECHNOLOGY by end-to-end coupIing of acrylonitrile. Effects of temperature, pH2and addition of various salts Electrolysed Seawater Plays Big Role in were considered. Sewage Disposal Method R. EALES, Chem. Engng, 1968, 75, (13, June I7), Patterns of Organometallic Reactions 172-174 Related to Homogeneous Catalysis Vertical electrolytic cells for the purification of J. P. COLLMAN, Accounts ckem. Res., 1968, I, (s), sewage by electrolysis with sea water have 136-143 platinised Ti anodes and plain steel cathodes. A revicw of reaction patterns involved in homo- The cells operate at 6 V dc. CJB have constructed geneous catalysis by transition metal complexes, one plant on Guernsey and another is under con- including those of Ru, Ir, Rh, and Pt. struction at Capenhurst in Cheshire. Platinum Metals Rev., 1968, 12, (4) 153 TEMPERATURE MEASUREMENT tection against flame above 145o'C is given by a three-layer cover of corundum, ZrO, and corun- A Platinum Resistance Thermometer dum. Protection against molten glass up to Calibration between 2 and 273.15"K IZOO~Cmay be afforded by corundum, or at tem- peratures &1200'C by a three-layer cover of CHAN YET-CHONG and A. M. FORREST, J. sci. corundum, steel and corundum. Protection Instrum.,J. Phys. E., r968, I, (81, 839-842 against molten glass above 1250°C consists of Selected Pt resistance thermometers were cali- corundum sheathed with Pt. In each case the brated approximately at 2-273.15"K using only thermocouple itself is supported in a twin-bore the b.p. of He, the ice point, and temperatures at corundum tube. 2-4.2"K from He vapour pressure thermometer measurements. Interpolation for 4.2-273. IS'K used a table of Z functions and for 2-16°K used Determination of Temperature According to a polynomial equation in T against R. the Thickness of the Clinker Deposit v. v. PUZANKOV, yu. P. SHCHUKIN and M. L. VISHNEVETSKII, Stal', 1968, (4), 304-305 Comparison between Gas Thermometer, Acoustic, and Platinum Resistance Tempera- To eliminate errors of temperature measurement with Rh-Pt thermocouples due to clinker build-up ture Scales between 2 and 20°K on the sheath a probe has been developed at the J. s. ROGERS, R. J. TAINSH, M. s. ANDERSON and c. A. Karaganda works which extends telescopically so SWENSON, Metrologia, 1968, 4, (2), 47-59 that the hot junction projects beyond the point of The NBS Pt resistance thermometer scale of 1955 clinker build-up. at 2-16°K was used in determining the resistance versus temperature relation of Ge thermometers Calibration and Stability of Miniature to *3 mdeg against a constant volume gas Resistance Thermometers thermometer. G. w. LINDBERG and w. v. JOHNSTON, Abstr. papers, 155th Mtg, Am. Chem. Soc., 1968, (Mar.), V9 Temperature Measurements with Metal Ribbon High-temperature X-ray Furnaces Miniature Pt resistance thermometers 0.5 in. long, 0.156 in. diameter, weighing I g were calibrated W. OSTERTAG and G. R. PISCHER, Instrum., Rev. sci. at - 182 to 100°Cby comparison with capsule- 1968J 39, (6), 888-889 type Pt resistance thermometers and at -262 to Thin Pt and Rh-Pt thermocouple wires were -182OC by interpolation data. The resistance at welded to the Pt ribbon of a high-temperature 0°C was reproducible to 10 ppm for six months. X-ray diffractometer attachment. The tempera- ture profile of the specimen stage, determined as The Accuracies of Calibration and Use of functions of temperature, heater position and I.P.T.S. Thermocouples heater shape, showed improved accuracy of tem- T. r. JONES, Metrologia, 1968, 4, (z), 80-83 perature measurement. Uncertainty expressed as ggon confidence limits from precise calibration of Pt : 1o0/,, Rh-Pt Protective Devices for Thermocouples Used thermocouples at 630.5-1063°C is z & 1.0 pV, in Glass-melting Furnaces based on five replicates at each of the three v. M. OBUKHOV, Steklo Keram., r968,25, (4), 12-14 primary calibration points and subsequent accur- Four types of protective casings for 64,)Rh-Pt: acy of a calibrated thermocouple with systematic 30:; Rh-Pt thermocouples arc described. Pro- errors eliminated is &o.z"C. NEW PATENTS METALS AND ALLOYS Producing Iron-RhodiumBase Alloys Having Improved Magnetic Transition Properties An Improved Alloy GENERAL ELECTRIC co. (NEW YORK) JOHNSON, MATTHEY & CO. LTD British Patent I,I 17,727 Bsitish Patent 1,112,766 An alloy with a CsC1-type ordered crystal struc- A new alloy, especially suitable for spinnerette ture and an antiferro-magnetic-ferromagnetic production, consists of 50-80u,, Au, 0.04-0. jot,lr, transition is obtained from an Fe-Rh alloy, and the remainder Pt with the usual impurities. optionally containing small amounts of Pd or Pt, Platinum Metals Rev., 1968, 12, (4), 154-158 154 by heat treating at a temperature above 800°C to coating of another metal, especially Pt group produce homogenisation of the alloy and then metal, without first removing the oxide film. By quenching the alloy to a temperature below 8dC. definition Pt group metal excludes Pd but in- cludes the other five metals. The Pt metal is Treatment of Palladium and Palladium-base applied in the form of an alloy with a very readily Alloys dissolved metal, such as Cu. JOHNSON, MATTHEY & CO. LTD British Patent 1,117,739 Deposition of Ruthenium British Patent I,O~I,O~Irelates to a method of JOHNSON, MATTHEY & CO. LTD treating Pd or its alloys to reduce discontinuous British Patent I,I 14,595 yielding under stress. This method may now be A porous base is impregnated with Ru (e.g. to applied to alloys in which Na has been added to produce Ru/Al,O, catalysts) by contacting it with suppress the formation of Pd silicide. a solution of (NH,),Ru(NO,),, and then decom- posing this compound to leave behind Ru metal. Production of Platinum and/or Palladium Oxides or their Mixtures with Rhodium, Palladium Electroplating Iridium or Ruthenium Oxides I.B.M. CORP. US.Patent 3,376,206 JOHNSON, MATTHEY & CO. LTD Catalytic fdms of high activity are deposited, German Patent 1,266,293 especially on Cu and its alloys, by using baths containing water-soluble salts of Pd and strong A composition comprising a powder of one or acids, buffering salts of weak bases and strong more of the above oxides is produced by the acids and organic complexing agents at pH anodic oxidation of Pd, Pt or a suitable alloy with 4-5.5, e.g. PdCI,, NH,C1 and disodium EDTA. the other Pt metals in a molten mixture of an alkali metal nitrate or chloride. Ceramic Metallising Paint E. 1. DU PONT DE NEMOURS & CO. Permauent Magnets U.S. Patent 3,380,835 DEUTSCHE GOLD- & SILBER-SCHEIDEANSTALT Successful metallising of ceramics with Pt group German Patent 1,266,511 metals, e.g. Pt and Pd, is achieved by deactivating Methods are provided for the heat treatment of these catalytic powders previously by heating or magnetic alloys containing Fe with 25-62 wt?; by treatment with As oxide, Sb oxide, etc. Pd, produced by melting or sintering. Chemical Platinum Plating Process Improvement of Metal Properties JOHNSON, MATTHEY & CO. LTD JOHNSON, MATTHEY & CO. LTD French Patent 1,512,175 Dutch AppZn 66.14~42 PtO,, alone or mixed with up to soo'; of another Noble metals, noble metal alloys and other metals Pt metal oxide, is reacted with a 2-5 C aliphatic (e.g. produced from powders) are cold worked to alcohol to give a dispersion. The dispersion is such an extent that during subsequent tempering, contacted with a substrate in the presence of recrystallisation occurs to give a grain structure H,O and a H,O soluble mineral acid to deposit highly oriented in the direction of cold working. Pt (or Pt alloy) on the substrate. The deposit is dried and organic material eliminated. CHEMICAL COMPOUNDS Applying Designs to Metallic Bases New Ruthenium Complexes JOHNSON, MATTHEY & CO. LTD STE USINES CHIMIQUES RHONE-POULENC Canadian Patent 785,472 French Patent 1,503,334 A metal or alloy differing in colour from the On contacting RuCl, or RuI, with certain nitrile metal base is applied in an organic base and fired or olefine ligands, new complexes are formed of to produce slight adherence, the metal or alloy formula RuX,L,, where m is z or 3 and n is then being embossed with a design. Au, Ag and 4 or 3, X is halogen and L is an olefine activated Pt metals, e.g. in flake form, are suitable decora- by certain groups, an aromatic nitrile or a satur- tive materials. This corresponds to French Patent ated aliphatic or cycloaliphatic nitrile. 1,455,917 and Italian Patent 767,740. ELECTRODEPOSITION AND JOINING SURFACE COATINGS High Temperature Brazing Alloys U.S. ATOMIC ENERGY COMMISSION Electrodes U.S.Patent 3,374,092 IMPERIAL METAL INDUSTRIES (KYNOCH) LTD W, Ta and their alloys are brazed using a ternary British Patent r,113,421 alloy of Ie-35 wtUjtiRu, 45-90 wt"to W, remainder A Ti core or a core of a similar metal is given a Re, melting at 2300-28007C. Platinum Metals Rev., 1968, 12, (4) 155 HETEROGENEOUS CATALYSIS Aluminosilicates Containing Platinum Metals Epitactic Ruthenium Catalyst MOBIL OIL COW. US.Patent 3,373,110 E. 1. DU PONT DE NEMOURS & CO. Pt metal impregnation of a synthetic zeoIite is British Patent I,I 13,405 achieved by adding a Pt metal salt solution The “epitactic” catalyst is a support of eta-Al,O, (especially containing a Pt or Pd salt) to the carrying an epitaxial growth of Ru. It is produced aluminate and silicate solutions from which the from RuCI, or nitrosonitrate solution which is zeolite is formed. adjusted to pH 3.5-4.5 with (NH&CO, or NH,HCO, and then mixed with a slurry of solid Selective Hydrogenation Catalyst eta-Al,O, particles. Further alkali is added to bring FARBENFABRIKEN BAYER A.G. the pH to 7.5-8.5 while heating at 45-85°C. U.S. Palent 3,373,219 After 20 min the precipitate is removed, dried The selcctive hydrogenation of 4C acetylenic and treated with H,. compound in a mainly butadiene fraction is improved when the fixed Pd catalyst is supported Production of 2,%-DimethylButane on a Li A1 spinel. UNIVERSAL OIL PRODUCTS CO. British Patent 1,1I5,176 High Octane Petrols The isomerisation to 2,3-dimethyl butane of neo- AIR PRODUCTS & CHEMICALS INC. hexane is catalysed at 100-50o‘C and 1-150 atm U.S. Patent 3,374,167 by a Group VIB or VIII metal on an acidic A full range reformate is hydrogenatively re- support, e.g. with small amounts of Pt !Al,O, F, formed over Pt’Al,0, a heart cut is removed and Cl,. For the highest yield, the rate of flow from the product and this cut is again hydro- of the neohexane should be such that 0.1-20 genatively reformed over Pt,’Al,O,. Less catalyst mole/, of it is converted in each pass. deactivation occurs. Catalytic Reactions and Catalyst Oxidisation Catalyst JOHNSON, MATTHEY & CO. LTD UNIVERSAL OIL PRODUCTS CO. British Patent 1,116,943 U.S. Patent 3,377,269 An improved catalyst for the isomerisation of The particles of catalyst are based on AI,O, with olefines, especially l-CsH,, is obtained by ab- a variable density of catalyst where a small part sorbing a catalytically active Pt group metal on to of the total surface has small localised spots of Pt a solid porous support from a thermally stable with a high density of ~o,ooo-~o,ooopg/m2 Pt solvent, e.g. using RhC1,.3H,O in ethylene and the remainder of the surface has a low glycol. density of the order of 0.9-10 pg,/m2 Pt, giving a total Pt content of 0.05-0.2 wt96. The catalyst Catalytic Cracking of Hydrocarbons can be used for burning I.C.E. exhaust gases. W. R. GRACE & CO. British Patent 1,117,210 The catalyst consists of 0.1-2 wt?/u Pd, Rh and/or Oxidisation of Waste Gases over Mixed Pt deposited on a Si0,-Al,O,-zeolite support. The support contains 10-40:(, uncombined Also, and Catalysts 5-80?; of a zeolite of formula ~M~/,O.~,0~.3.5-UNNERSAL OIL PRODUCTS CO. 7SiO2.o-gH,O, where M is a cation of valency n U.S. Patent 3,378,334 and x is 0-1. 1,117,209 describes the same catalyst Combustible gases (e.g. T.C.E. exhaust gases) are supports used for Co and Ni catalysts. mixed with 0, and passed over a fixed bed of spherical Pt catalyst particles, some of the particles Selective Hydrogenation (8-30q/”) having a Pt content up to about 57; and the remainder a low Pt content so that the overall CATALYSTS & CHEMICALS INC. content is wtx. British Patent 1,120,307 0.05-a2 Small amounts of C,H, in CPHl are selectively Olefin Hydroformylation hydrogenated by adding an excess of H, and passing the gas mixture over a supported I’d TOA NENRYO K.K.K. U.S. Patent 3,378,590 catalyst in the usual way. The selectivity is The production of aldehydes and alcohols from improved by adding 5-400 ppm of CO to the olefins, H, and CQ is catalysed by Co promoted olefin. with Pd/C or Pt/C. Platinum Gauze Catalyst Activation Gas Reactions Using Gauze Catalysts MONSANTO CO. US.Patent 3,371,989 MONTECATINI-EDISON S.P.A. The reaction over a Pt gauze of KH,, natural gas US.Patent 3,379,500 and air to give HCN is improved by flowing the Specific mixtures of NH,, CH,, N, and 0, are reactants over the gauze at 1.28-1.45 lb/hr/layer reacted over gauze catalysts made of Pt or its of gauze/in2 in order to activate the catalyst. alloys at Ixoc-rzoo’C. Platinum Metals Rev., 1968, 12, (4) 156 Low Pressure Platinum Reforming Catalyst Olefin Oxidative Carbonylation UNIVERSAL OIL PRODUCTS CO. UNION OIL CO. OF CALIFORNIA US.Patent 3,379,641 US.Patent 3,381,030 Low pressure reforming is catalysed by a sul- Olefins, 0, and COz react to give unsaturated phided Pt-Fe-halogen;Al,O, catalyst having an Fe carboxylic acids and aliphatic esters in the content of 100-1000 ppm, uniformly distributed presence of an anhydrous organic solvent solution throughout the catalyst. containing 0.01-5 wtu/, Group VIII metal, especially Pd, in a redox system at 30-300°C and Hydrogenation of Olefine Polymers in at an elevated pressure. Cumene GULF OIL CORP. U.S. Patent 3,379,767 Olefine Polymerisation Catalysts Cumene contaminated with olefin polymers is INSTITUT FRANCAIS DU PETROLE, DES CARBURANTS passed over a PdL/Al,O, catalyst in a fixed bed at ET LUBRIFIAKTS French Patent 1,505335 1oo-3oo"F in the presence of H, to hydrogenate The specificity and activity of Ziegler catalysts is the olefin polymers. improved by the introduction of a Group VIII noble metal salt or complex, preferably a complex Oxidation of Glucose produced in situ. Thus a complex of PdCl, and JOHNSON, MATTHEY & CO. LTD PPh, can be formed in the presence of Et,AlCI Dutch Appln 67.13391 and TiCl,. Selective oxidation is achieved using a supported Pt metal catalyst (e.g. Pd) in the presence of Na Production of Fnmaric Acid and Muconic or R carbonate or bicarbonate, Acid Dichlorides BADISCHE ANILIN- & SODA-FAERIK A.G. HOMOGENEOUS CATALYSIS German Patent 1,263,752 Ethylenic Compounds The reaction of C,H,, CO and PH, is catalysed by 0.001-5 wt:& of Pd or a Pd compound at IMPERIAL CHEMICAL INDUSTRIES LTD 50-12ooC and 50-300 atm gauge. British Patent 1,111,714 Vinyl or ally1 alkyl ethers are produced by con- Production of Alken-2-yl-I-ethers tacting a vinyl or ally1 ester of an aliphatic car- CONSORTIUM FUR ELEKTROCHEMISCHE INDUSTRIE boxylic acid with a 1-20 C aliphatic alcohol in the G.m.b.H. German Patent 1,269,613 presence of an organic solvent containing o-100/; H,O and a salt or coordination compound of a Pt The production of these ethers by the reaction of the corresponding halides with alcohols is metal, especially Pd, Pt, Rh and Ru. Typical catalysts are Li,PdCl, and Pd(OOC.CH,),. catalysed by Group VIII noble metals, especiaIly Pd and Rh halides or halide complexes, e.g. Producing Vinyl Acetate Na2PdC1,. ASAHI KASEI K.K.K. British Patent 1,116,588 The reaction of C,H, and 0, in the presence of a FUEL CELLS chloroacetic acid to give vinyl acetate is catalysed by oxides, hydroxides and salts (readily reacting Fuel Cells with acetic acid to give acetates) of Pt, Pd, Ru, Rh JOHNSON, MATTHEY & CO. LTD or Ir promoted with Cu, Ag, Cd, Sn, Pb, Cr, Mo, British Patent 1,111,864 W, Fe, Co or Ni. A H,-0, cell fed with NH, is fitted with a fuel electrode made of a base metal, Pd or Pd alloy Manufacture of Vinyl Esters permeable to H, on which the NH, is decom- COURTAULDS LTD British Patent 1,116,945 posed. The oxidation of C,H, in the presence of a carboxylic acid to form a vinyl ester is catalysed In Situ Preparation of Hydrogen and Simul- by a circulating liquid solution of a palladous taneous Hydrogen Control in Electro- carboxylate, a metal salt able to oxidise Pd metal chemical Cells and an alkali metal carboxylate. The reaction PROTECH INC. British Patent yields Pd metal as a by-product and this is heated 1,114,851 with a carboxylic per-acid to regenerate the H, utilisation in a fuel cell is controlled by using palladous carboxylate. an anode structure coated with a layer containing Pd, (e.g. a Pd-Ag alloy) permeable only to H,. Production of Vinyl Carboxylic Esters CELANESE CORP. British Patent I,IZI,IO~Ion Exchange Membrane Electrode A vinyl ester of a 2-7 C aliphatic acid is produced GENERAL ELECTRIC co. (NEW YORK) from C,H,,the 27C acid and 0, in the presence British Patent 1,120,267 of halogen, cupric, Pd and 27 C acid ions, the Electrodes particularly suitable for fuel cells are Pd and Cu being present in at least 0.00~and produced by electrolytically depositing a thin 0.2 M concentrations respectively. layer of catalytically active noble metal (especially Platinum Metals Rev., 1968, 12, (4) 157 Pt) on a conducting base, washing and drying the Materials for an Electric Contact deposit and finally transferring the deposit by HITACHI LTD British Patent 1,116,788 physical contact to the surface of an ion exchange Electrical contacts are made from I'd containing membrane. Pt alloy deposits may be produced 0.1-10 wt% of a Pb compound or compounds. and transferred in the same way. Preferably 0.1-10wt'ji, of PbS and/or PbO are introduced into Pd by sintering or by addition to Platinum-coated Fuel Cell Electrode molten Pd. TEXACO INC. U.S. Patent 3,377,204 A porous C electrode is treated to incorporate Pt Metal Glaze Resistance by heating the electrode in CO, at 700-1000°C INTERNATIONAL BUSINESS MACHINES CORE'. for 1-10 hours, coating the electrode surface with US.Patent 3,372,058 H,PtCl,, reducing the acid to Pt metal at zoo- Resistances are produced on ceramic dielectrics 300°C for 1-4 h in a H, atmosphere and finally by applying and firing a glaze containing I 5-700; heating the electrode at 700-1000'C for 1-10 h PdO or Rho, having a crystallite size with a in a H, atmosphere. surface area of at least 0.75 m2/g, and up to 357;, of a conductive metal, such as Ag, dispersed in Vapour Diffusion Fuel Cell Electrode 35-70?; vitreous enamel frit. MONSANTO RESEARCH CORP. U.S. Patent 3,382,103 Conductive Noble Metal Paint N,H, is supplied to the fuel cell anode through a INTERNATIONAL BUSINESS MACHINES CORP. three-layer barrier of which the central layer U.S. Patent 3,374,110 contains a N,H, decomposition catalyst such as An alloy of 75-85"/bAg and 2j-15X Pd is pro- Ru or Rh. duced and powdered for use with a ceramic frit to give a conductive paint. This alloy, unlike pure Fuel Cell Electrode Assembly Ag, does not migrate and can be soldered. U.S. NATIONAL AERONAUTICS & SPACE ADMINISTRA- TION U.S. Patent 3,382,roj Piezoelectric Lead Zirconate Titanate The electrode assembly consists of thin plastic NIPPON ELECTRIC GO. LTD US.Patent 3,375,194 ion exchange membranes coated with finely The electromechanical coupling and mechanical divided Pt catalyst. qualities of these ceramics are improved by incor- porating 0.01-r.0 wtyh of Rh,O,. CATHODIC PROTECTION Sintered Palladium Electrical Contacts Electrodes with Activated Platinum Group HITACHI LTD U.S. Parent 3,380,812 Coatings Electrical contacts for use in an organic gas ORONZIO DE NORA IMPLIANTI ELECTROCHIMICI atmosphere are made from Pd with an added British Patent I,I 11,767 inorganic Pb compound, e.g. litharge, to reduce An electrode for impressed current cathodic pro- its catalytic action and thus eliminate the forma- tection has a solid base (e.g. of Ti) coated with a tion of brown deposits when operating in organic gases. Pt metal containing 0.2-2 wt%, of Sb, Cd, Pb, Cu, Ta, V, Nb or their mixtures as activating element. Preferably a coating of Pt containing Sb TEMPERATURE is applied to a Ti base. MEASUREMENT ELECTRICAL AND High Temperature Thermocouples ELECTRONIC ENGINEERING GENERAL MOTORS CORP. British Patent I,I 14,874 Balanced thermoelements and leads comprise Cermet Resistance Element (a)a thermoelement of 40:$ Pd, 50"; Pt and IOO:, BECKMAN INSTRUMENTS INC. Au, (b) a second thermoelement made of 65% Au British Patent I,I 12,474 and 35:4 Pd, (c) one lead of chrome1 and (d) a A resistance layer of low coefficient of resistivity, second lead made of a Ni-Fe-Mn alloy. for brazing to a non-conducting base, consists of j0-950//0glass and jo-Ioo/;,of a Ru-Rh alloy. Improved Vessel for Molten Metals Thus a layer can contain So":, glass, IO", Ru and YAWATA IRON & STEEL CO. LTD 1oyc1Rh. British Patent 1,117,935 In order to make measurements on molten metals, Resistive Elements for Variable Resistors the vessel is fitted with a standard electrode for AMPHENOL CORP. British Patent I,I 14,052 measuring the 0, content electrochemically. The Low noise characteristics are obtained by coating standard electrode is also matched with a metal an insulating base with a Ni-Cr-Fe alloy and wire, e.g. a Pt-Rh wire, to act also as part of a applying a film of Pt, Rh or Ir. thermocouple to measure the temperature. Platirium Metals Rev., 1968, 12, (4) 158 AUTHOR INDEX TO VOLUME 12 Page Page Page Puge Ahdulov. R. Z. 68 Coffey, R. S. 36 Gilroy, D. 148 Kelarcv, V. V. 68 Aben, P: C. 136, 151 Collman, J. P. 153 Giner, J. 32 Kenahan, C. B. 20, 70 Abubaker, M. 1 13, I52 Colton, R. 111 Ginzhurg, S. T. 147 Kcdks, G. W. 112 Aeuil6. A. 73 Connolly, J. F. 31 Gohle, R. 30 Khrustova, Z. S. 152 Aibright, L. F. 74 Connor, H. 48 Gorhachcva, N. B. 73 Khulhc, K. C. I36 Aliradc, Z. I. 68 Conway, B. E. 148 Gostunskaya, I. V. Kiperman, S. L. 136 Allard, K. 109 Cook. E. H. 148 113, 150 Kitazume, S. 111 Allen, A. D. 70, I I1 Cramer,R. 31, 153 Graham, A. R. 151 Kjckshus, A. 68 Anderson, J. R. 33 Cramer, S. D. 20 Greenfield, H. 72 Klyushin, V. V. 68 Andrcs, K. 110 Csicsery, S. M. 33 Greenwood, J. H. 146 Kogan, S. B. 71, 151 Andrews, R. L. 70 Greig, D. 29, 109 Kohlhaas, R. 29 Andrianov, M. A. 69 Griftith, W. P. 31, 47, Kohling, A. 148 Angus, H. C. 129 Damjanouic, A. 31 138 Kohll, C. F. 152 Arons, R. R. 30 Darby, J. B. 108, 109 Grigor’ev, A. A. 114 Kolbin, N. I. 110 Astley, D. J. Ill Darling, A. S. 7, 54, ??,. Grothcer, M. 1’. 148 Koncv, V. N. 69 Alery, N. R. 33 ILL Gryaznov, V. M. 15 1 Kriiek, J. 72 Dauhy, R. 74 Gurevich, M. A. 30, 141. Krone, H. 70 Davies, N. W. 1I4 146 Kruglov, A. A. 69 Babitskii, B. D. 31 Davies. T. A. 129 Gutt, w. 86 Kudryavtsev, N. ’I. I12 Bagroua, V. 1. 69 Davlesupova, R. G. 72 Gnzci, L. 136 Kiihn von Burgsdorf, Bailar, J. C. 35 Dawans, F. 74 J. W. 153 Baker, R. H. 151 Despic, A. R. 153 Kurkchi, U. M. 151 Balandin, A. A. 71, 112 Diehl, W. 6 Ham, R. C. 108 Kutaitscv. V. I. 69 Bamford, C. H. 1 13 Di Michiel, A. €5. 114 Hammar, R. R. 147 Bartlett,N. 31, 14X Dinges, H. W. 129 Hansel, G. 32 Becker, K.-E. 149 Djerassi, C. 74 Hare, T. 129 Lancwala. M. A. 72 Beckey, H. D. 71 Donati, M. 73 Harrison, D. E. 70 Bedcll, J. 70 Larenbv, F. 120 K. Dorling, T. A. 33 Harrison. J. A. 111 leach, A. 30 Bedford, R. E. 115 Dovcll, F. S. 72 Hartog, F. 136 Bedi, R. D. 149 Lebedev, 1. G. 69 Drazic, n. M. 153 Hashintoto, E. 146 Lcpselter, M. P. 106 Bekauri, N. G. 73 Drowart, J. 69 Haydcn, H. W. 31 Bcrndt. A. F. 110 Lewis, F. A. 30, 140 Druz’, V. S. 72 Heil, B. 1 I4 Liberman, A. L. 136 Berry, R. J. 36 Dubinin, E. L. 67 Hellicr, M. 35 Bertodo, R. I06 Lileikina, T. N. 73 Dubinin, S. F. 67 Hendrieks, J. W. 36 Lindberg, G. W. 154 Beznosikova, A. V. 69 Dubperncll, G. I49 Henry, P. M. 35 Bidwell, L. 109 Linscn, B. G. 35 K. Dummer, G. 68 Heyding, R. D. 69 Litvin, E. F. 152 Binder, H. 148 Durigon, D. D. 112 Hiddleston. J. N. I1 1 Llewellyn-Jones, F. 129 Bittlcr, K. 153 Dwight, A. E. 110 Hinkins, B: 86 Blasse, G. 75 Lobach, M. 1. 31 Dzhardarnaliera. K. K. 72 Hiscocks, S. E. R. 108 Lovinskaya. E. N. 75 Bohmoldt, G. 67 Ho, N. S. 146 Boiko, R. T. 146 Lukashenko, G. M. 109 Hoare, J. P. 70, 148, 149 Lupu, N. Z. 75 Bond, G. C. 35, 71, 100, Hoehstra, H. R. 69, 147 136 Ealcs. R. 153 Eastmond, G. C. 113 Hoffman, H. M. 108 Booth, J. G. 110 Hohnke, D. 68 Elliott, C. T. 108 MeClure, J. D. 114 Borod’ko, Yu. G. 69 Engdahl, R. E. 70 Holland, H. B. I13 Boronin, V. S. 72, 136 Holleck, G. 67 MeDaniel, C. L. 147 Entina. V. S. 70. 149 McDonald, D. 142 Borunova, N. V. 11 3 Eremenko, N. K. 73, 109 Homma, M. 146 Bottomley, F. 70, 11 1 Hopkins, J. R. 150 McElroy, D. L. 36 Bragin, 0. V. 34, 136 Erivanskaya, I. A. 150 Mclnerney, h. J. 21 Esin, 0. A. 30, 67 Horrex, C. 136 McKec, D. W. 21, 34, Brailovskii, S. M. 114 Horiuti, J. 136 Brcitbach, H.-K. 110 Hunter, J. B. 2 153 Breitenstein, A. M. 31 Huntington, R. D. 30 Mackliet, C. A. 109 Breiter, M. W. 148 Fairweathcr, A. 129 Hussey, A. S. 112, 151 Macklin, R. A. 62 Bril, A. 75 Farthing, R. H. 11 1 Macnab, J. I. 151 Brodersen, K. 69, 110 Fasman, A. B. 33, 152 McNiff, E. J. 61 Brookes, C. A. 146 Fedorov, I. A. 63 Iles, G. S. 99 McQuillan, F. J. 1 I3 Brown, C. B. 14 Fedot’ev, N. P. 32 Tmamova, R. M. 110 Maeland, A. 109 Brummer, S. B. 148 Fergusson, J. E. 1 1 I Indzhikyan, M. A. 7 I Magat, L. M. 109 Brusic, V. 31 Figucras, F. 113 Irwin, W. J. 113 Mahle, E. 112 Buckley, D. H. 61 Filonenko, A. P. 71 Isabekov, 4. 33, 152 Makarova, G. M. 109 Burch, R. 30 Firth, J. G. 113 Maldonado, K, 151 Burgert, W. 73 Fischer, G. R. 154 Mal’tsev, A. E. 33 Burnett, R. L. 33 Fitoussi, L. 107 Jackson, J. J. 108 Manchcster, F. D. I46 Bursian, N. R. 71, 151 Flannery, R. J. 31 James, B. R. 114 Mann, R. S. 113, 136, Fletcher, J. M. 31, 111 Jamcs, S. D. 70 152 Fletcher, R. 29, 109 JaroTs, S. 72 Mano, K. 129 Cahill, K. 148 Floreen, S. 31 Jensen, M. A. 110 Markina, M. T. 73 Cairns, E. J. 21, 31, 115 Flynn, D. R. 108 Johnston, W. V. 154 Marko, H. 114 Cairns, J. F. 114 Pomichev, Yu. V. 150 Jolliff, E. 149 Martin. J. J. 29 Caputo, J. A. 34 Foner, S. 67 Jones, D. J. 30 Manet, H. V. 70 Camenter. R. W. 29 Forrest, A. M. 154 Jones, T. P. 154 Mashkina, A. V. 73 car&,s. 34, 151 Freidlin, I,. Kh. 113, 152 Masumoto. H. 146 Chabria, J. R. 70 Fuchs, R. 34 Mather, W. B. 74 Cbalisova. N. N. 147 Fusy, J. 150 Kadaner, L. I. 150 Matveev, K. I. 73 Chan Yetkhong 154 Kaliya, 0. L. 1 I4 Medvanik. C. N. 150 Chatt, J. 111 Kammel, A. 111 Mci& zu Kiicker, H. 34 Chaudron, G. 13 Garanin, V. T. 151 Kaneko, H. 146 Memon, N. A. 114 Chauvin, Y. 73 Gardner, R. A. 136 Karn, F. S. 19 Mencier, B. 113 Chebotarev, N. T. 69 Gardner, W. E. 31, 11 1 Karoova. T. P. 110 Merta, R. 136 Chernyaev, 1. I. 146 Garnett. J. L. 113 KaGhev,’ V. I. 112 Minaehev, Kh. M. 72 Citron. J. D. 35 Gault, F. G. 136 Katzschmann, R. 36 Misono, A. 153 Clark,‘C. R. N. 82 Geiken, G. W. 67 Kaufman. L. 68 Misono, M. 151 Cleare, M. J. 31, 131 Gelhiu. D. 33. 150 Kazanskii. B. A. 71 Moiseev, 1. T. 114 Cobb. J. T. 74 Cerasimova, V. A. ‘ 73 Keii, T. 136 Mollernd, R. 68 Cockayne, B. 16 Giessen, B. C. 110 Keil, A. 112 Moss, R. L. 33, 34 Platinum Metals Rev., 1968, 12, (4), 159-164 159 ~.Parre Pace 0- Page Pnae Moyes, R. B. 136 Pregaglia, G. 73 Shibano, T. 153 Tsuji, J. 74, 114, 152 Miiller, E. W. 29 Preston-Thomas, H. 1 IS Shier, G. D. 152 Tuyn, C. 30 Miiller, H. 113 Psaronthakis. J. 30 Shilova, A. K. 69 Tyrrell, C. J. N. 112 Muller;Muller, J.J. M.M. 136 Puiankov. V: V. 154 Shimim, S. 146 Muller,Muller, L.L. R.R. 147 Shoemaker, G. E. 108 MuIIer,Muller, 0.0. 69 Shchukin, Yu. P. I54 Uchida, Y. 153 Murray,Murray, J.J. J.J. 69 Raevskaya, E. I. 75 Shuikin, N. I. 73 Ustinom, T. S. 71 Myles,Myles, K.K. M.M. 108, 109 Ragaini, V. 34, 151 Shreir. L. L. 42 Utegulov, N. I. 72 Rao, P. R. 31 Shultg J. F. 19 Rauh, E. 30, 109 Sidles, P. S. 29 Naik, S. C. 152 Rayne, J. A. 108 Sidorov. S. K. 67. 68 Van Bekkum, H. 35 Nakamura. A. 74 Recchia, A. 32 Sieael. 8. 69. ’1 47 Vander Auwera- Nefedov, 0. M. 152 Reinacher, G. 68 Simons, E. I,. 115 Mahieu, A. 69 Ng, F. T. T. 114 Rhodes, D. R. 150 Sinfelt, J. H. 34, 73 Van Gogh, J. 35 Nicolau, I. 151 Rienacker, G. 113 Sinitsvn. N. H. 73 Van Hardeweld, R. 136 Niedrach, L. W. 21 Ritchie, A. W. 33 Slovokhotova, T. A. I52 Van Helden, R. 152 Nikulina, V. S. 72 Rizzo, F. E. 109 Smcaton, W. A. 64 Van’t tlof, L. P. 35 Nixon. A. C. 33 Roberts, H. L. I14 Smith, G. V. 136 Van Vucht, J. H. N. 134 Norman, J. H. 69 Rodina, A. A. 30, 141, Smotritskaya, E. S. 69 Vatolin, N. A. 30 Novik, F. S. 75 146 Sokol’skii, D. V. 72, 150 Vidaurri, F. C. 151 Novikov, I. I. 75 Rogers, J. S. 154 Solomon, D. E. 150 Vinogrador, S. N. I12 Hosehcl, E. 109 Solov’e\a, N. A. 147 Vlasov, Y. G. 67 Rossinzton. D. R. 33 Sommer, L. H. 35 Voelter, W. 74 Obukbov, V. M. 154 Roy, R’. ’ 69 Spangenberg, 6. D. 32 Von Kutepow, N. 153 Ocken, H. 134 Riidorff, W. 111 Speicher, C. A. 149 Voronin, V. V. 72 Oftedal, E. 68 Runk, R. B. 33 Spitsyn, V. I. 71, 112 Vyacheslavov, P. M. 32 O’Hagan, M. E. 108 Russell, B. C. 32 Staley, H. G. 69 Ohno, K. 114 Russell, D. C. 29 Starostenko, G. K. 152 O’Keefe, J. H. 113 Rytvin, E. I. 75 Stepakoff, G. 68 Wallace, W. E. 67 Okhotin, M. V. 75 Ste$ens, J. M. I49 Walter, G. 67 Orkin, B. A. 150 Stelenson, R. D. 62 Wang, R. 110 Ostertag, W. 154 Saito, H. 146 Warncr. T. B. 148 Saito, Y. 151 StOssel, A. 111 Otsuka, S. 74 Sze, S. M. 106 Warren; R. 108 Owyang, R. 1 I4 Samoilov. V. M. 110 Wayne, R. C. 110 Samsono;, G. V. 75 W7ebb. A. N. 74 Sandler, Y. L. 112 Webb; G. 151 Palatnik, L. S. 146 Sarmurzina, A. G. 72 Tainsh, R. J. I54 Weber, B. 1 50 Papke, J. A. 62 Savitskii, E. M. 63 Takahashi, H. 74, 152 Weiss, W. D. 29 Park, J. J. I47 Searpellino, A. J. 153 Takahashi. S. 153 Wicke. E. 67 Parravano, G. 34 Schaake, H. F. 146 Takamura; A. 53 Wilde,‘E. 33 Parry, J. M. 32 Schindler, A. I. 109 Takei, T. 1 I1 Wilenzick, R. M. 29 ParthC, E. 68 Schlain, D. 70 Tallan, N. M. 75 Wilkinson, G. 50, 135 Paryiehak, T. V. 33 Schlegel, H. 149 Tao, Lun-Svan 34 WilIiamson, J. B. 129 Penman, B. D. 147 Schmidt-Brncken. H. 129 Taube, H. 70 Wise, E. M. 98 Petrii. 0. A. 70, 149 Schneider, S. J. 147 Tayim, H. A. 35 Withers. J. C. 62 Petrov, P. N. 69 Sehriher, T. J. 34 Taylor, G. F. 71 Wollaston, W. H. 66 Phung, N. H. 73 Schriempf, J. T. 67 Taylor, W. P. 112 Pichler. H. 34, 73 Schuldiner, S. 148 TCt8nvi. P. 116 Pickcrt, P. E. 72 Schumacher, D. 108 TCGsk,’ P: 74 Yakovlev. V. I. 75 Pimhley, W. T. 149 Schwerdtfeger, K. 147 Thiele, C. 69 Yamamoto, A. 111 Plateeuw. J. C. 136 Seeser. A. 10s Thomas, B. R. 129 Yates, D. J. C. 34, 73 Polak, J.’ 29 Segnan, R. 29 Thomas, D. H. 34 Yudkevich. M. I. 147 Polkovnikov, B. 11. 152 Selman, G. L. 7, 92, 122 Thomas, J. R. 30 Poltorak. 0. M. 136 Semenova, T. A. 73 Thomson, S. J. 71 Polyakova, V. P. 63 Shannon, R. D. 147 To, D. E. 113 Zakharov, A. I. 30 PoneE, V. 136 Shavolina, N. V. 1 12 Toenshoff, D. A. 36 Zakumbaeva, C. D. 148 Pospelova, R. V. 68 Shaw, B. L. 89 Toktabaeva, F. M. 148 Zheligovskaya, N. N. 146 Powell, A. R. 22 Sherwood, H. P. 71 Tonmanor,, T. 72 Zwell, L. 147 Pratt, J. N. 109 Shevtsova, G. A. 150 Tsong, T. T. 29 Zysk, E. D. 36 SUBJECT INDEX TO VOLUME 12 a-abstract Page Catalysts (Contd.) Page Air Pollution, control in HNO, plants 2 Ir/C, isomcrisation of licxcnes on, a 1 I3 34 Banks, Sir Joseph, Janety writes to 64 Ir/Si02,liydrogenolysis of C,H, on, a Brazing, dissimilar metals, with Pd alloys, n 150 Os/C, isomcrisation of hexenes on, a 113 Pd alloys for 105 OsO,, oxidation of olefins on, u I I4 Palladium, alloys, activity of, a 72 Capacitors, monolithic ceramic 46 black, specific surface of, LI 71 Carbon, in steel-making, determinafion of 82 black, surface area of, a 151 Cardiac Pacemaker, Pt plating in, n 32 borided, hydrogenation of double Catalysis, activity of blacks, a 112 bonds on, a 152 homogeneous, organometallic reactions complexcs, carbonylation of olcfins in, a 153 on, a 153 Pt metals in, 4th International Congress on 136 complexes, dimerisation of butadiene Catalysts, for fuel cells 21 with, a 153 metals, periodic variations in properties of 100 complexes, hydrogenation of Iridium, interactions of Hz,and CO on, a 34 polyolefins by, a 35 complexes, decomposition of HCOOH complexes, isomerisation of by, a 36 n-phenylbutenes by, a 114 complexes. for homogeneous complexes, oxidation of olcfins by, a 73 hydrogenation, a - 114 complexes, unsaturated compounds IrH,(PPh3),, hydrogenation of aldehydes on, a 152 by, a 36 dehydrocyclisation of paraffins by, a 71 Platinum Metals Rev., 1968, 12, (4) 160 Catalysts (Contd.) Page Catalysts (Contd.) Page halide complcxcs, organic syntheses dehydrogenation of decalin on, a 33 with, a 152 dcutcration of alkanes on, a 33 hydrogenolysis of cyclopropanes at, a 113 cxoelectronic emission of, n 71 oxidation of CIH, on, a 113 fluorided, hydroisomerisation of solublc, polymerisation of allcne with, a 152 n-paraffins, on a 150 tape, dehydrocyclisation of hydrogenation of cycloalkencs from n-CaHla,a IS1 the liquid on, a 112 Pd(acac),!SiO, isomerisation of CaH hydrogenation of cycloalkcnes on, a 151 on, a 151 hydrogenation of mcthylcyclopentane PdCI,, activity of olcfin complexes of, a 73 on, a 72 complexes, carbonylation by, a 74 promoted, dehydrocyclisation of convcrsion of acetylenc compounds paraffins on, a 151 by, a 114 reduction of nitrogen oxides on, a 72 dccarbonylation of acyl halides by, a 114 retention of H, by, a 71 isomerisation of a-olefins, LI 114 surface transport of gases on, a 150 PdCI2-CuCI, oxidation of cyclohcxene by, a 3.5 Pt/asbestos, hydrogenation of C,H, on, a 72 oxidation of olcfins by, a 35 PtiC, hydrogenation of mcthylcyclopentane PdC1,-TiCI,. uolvmerisation of olcfin on, a 72 mxturcs b?, 1; 73 organosilicon hydride reactions on, a 35 Pd/Alr03,disproportionation of Pt/SiO,, activation energy of, a 33 cyclohexcnc on, a 34 C,H, hydrogcnation, specific activity hydrogenation of 6-mcthylhepta-3, of, a 112 5-dien-2-one on, a 113 chemisorption of 0, on, a 72 isomerisation of I-CIH, on, a 151 dehydrogenation of cyclohexanc on, a 113 organosilicon hydride reactions on, a 35 hydrogenation of C,H4 on, a 151 reduction of nitrogen oxides on, a 72 hsdroenalion of methvlcvclonentane .- .~ I retention of H?by, a 71 on, a 72 surface area of, a 151 hydrogenolysis of C2H, on, a 34 Pd/CaCO,, hydrogenation of isomerisation of PC~H,~, 6-mcthylhepta-3, 5-dien-2-one on, a 113 1-methyl-2-cthylbcnzene on, a 33 Pd/C, organosilicon hydridc reactions on, a 35 promoted, dehydrocyclisation of Pd/clay, convcrsion of C,H, and uaraffins. on a 151 naphthalcnc derivativcs on, a 73 structure and activity of, a 33 Pd/SiO,, hydrogenolysis of C,H, on, a 34 surfacc ared of, N 72 surface area of, a 151 Pt/Torvex, for air pollution control at Pd/TiO 1, hydrogenation of 6-mcthylhcpta- HNOI plants 2 3, 5-dien-2-one on, a 113 Pt/zeolite, hydrogcnation of methyl- Pd/zeolite, isomerisatioii activity of, a 72 cyclopentane on, a 72 Pd-Ru, deactivation of, by S-organic isomerisation activity of, a 72 compounds, a 73 isomerisation of cyclohexane on, a 15 1 Pd-Ag, decomposition of HCOOH on, Pt-Ru, hydrogenation of organic activity of, a 113 compounds on, a 72 film, oxidation of CzHIon, ,a 34 Pt-Ag, hydrogenation of C,H, on, a 71 film, para-ortho H2conversion on, a 33 Pt-Sn, complexes, hydrogenation of Palladium Sulphlde, hydrogenation of cyclohcxene by, a 35 halonitrobenzenes on, a 72 hydrogenation of 1 -liexcne, unsaturated Platinum, activity in solution of, a 148 edible 011~by, a 35 atomisation of O2on, a 150 isomcrisation of 1-C5H,0by, a 35 black, activation energy of, a 33 Platinum Sulphide, hydrogenation of black, spccific surface of, a 71 halonitrobenzenes on, a 72 borided, hydrogenation of double Raneg Ni-Pd, electrooxldation of H2and bonds on, a 152 hydrogenation on, a 33 complcxcs, oxidation of CO by, a 73 Raney Ni-Ru, oxidation and hydrogenation complexes, hydrogcnatioii of on, a 152 polyolcfiiis by, a 35 Rhodium, activity of, a 73 compounds, isotopic H labelling by, a 113 black, specific surface of, a 71 dehydrocyclisation of paraffins on, a 71 borided... hydrogenation - of double bonds clcctrode, H2-0,rcaction on, a 148 on, a 152 halide complexes, organic syntheses carbonyls, hydrogenation of with, a 152 aldehydes on, a 114 hydrogenolysis of cyclopropanes at, a 1 I3 complcxes, decarbonylation of interaction of HI and CO on, a 34 aldehydes and acyl halides on, a 114 isomerisation of alkanes on, a 33 complexes, decomposition of HCOOH powdey, isotopic exchange of 0, on, a 112 by, a 36 Pt@'Ph3)a, initiation of vinyl complexes, dimcrisation of polymerisation by, a 113 acrylonitrile on, a 114 Pt-Cu, hydrogenation of CoH,on, a 71 complexes, hydrogenation of stcroids Platinum Metals, activity of, a 72 by, a 74 hydrogenolysis of cyclic complexes, polymerisation of allene hydrocarbons on, a 71 by, a 74 review of, in industry, a 71 ions, reactions of olcfins at, a 153 tcrtiary phosphine complexes, interaction of Hr and CO on, a 34 homogeneous 50 phosphine complexes, homogeneous 135 Platinum Metals& isomerisation of RhCI,. conversion of acctvlenic comoounds dialkylcyclanes on, a 34 with. a 114 isomerisation of methylpentenes on, a 152 polymerisation of butadiene by, a 74 Platinum Metals/pumice, hydrogenation of RhCI,(SEt,),, hydrogenation of olcfinic allene on, a 113 substrates with, a 114 hvdroeenation of mcthvlacctvlenc on, a 152 Rh/AlaOa,hydroisomerisation of Pt/A1,03, activation energy of, a 33 1-C,H, on, a 151 aromatisation of n-paraffins on, a 150 organosilicon hydride reactions on, a 35 C,- and C,-dehydrocyclisation on, a 150 retention of H, by, a 71 conversion of C,H, on, a 112 Rh/C, isomerisation of hexenes on, a 113 dehydrocyclisation on, a 71 organosilicon hydridc reactions on, a 35 dehydrocyclisation of Rh/SiOh activity of, a 73 2-n-butylnaphthalcne on, a 150 hydrogenolysis of C2H, on, a 34, 152 dehydrogenation of cyclohexane 011, a 151 hydroisomerisation of I-CaHson, a 151 Platinum Metals Rev., 1968, 12, (4) 161 Catalysts (Cuntd.) Page Electrodes (Cunfd.) Page Rhodium Sulphide, hydrogenation of Pt-Ru, compact and dispcrsed, n 70 halonitrobenzenes on, a 72 in fuel cell$, n 153 Ruthenium, black, specific surfacc of, a 71 oxidation of CH,OH on, a 70, 149 complexes, dimerisation of acrylonitrile Rhodium, bright, 0,overvoltage on, a 149 with, a 114 reaction with 02,a 70 hydrogenation of sulpholene on, n 53 Ruthenium, oxidation of CH,OH on, a 149 hydrogcnolysis of C,H, on, a 152 Ru-Pt, compact and dlspcrscd, CI 70 interaction of H, and CO on, n 34 in fuel cell?, a 153 phosphine complexes, homogeneous 135 oxidation of CH,OH on, a 70 149 polymcthylcne synthcsis on, a 73 Schottky Diodes, Pt silicidc In ’ 106 RuCI,, dimerisation of acrylonitrile by, a 153 Ag-Pd, cathodes, for H purification 15 Ru/AI2O3,methanation over I9 oxidation of NH? on, a 34 Field Ion Microscopy, Pt, n 149 RUE,hydrogenation of olefins on, u 152 Pt emitters for, a 71 isomerisation of hcxciies on, a 113 study of Pt3Co by, a 29 organosilicon hydridc reactions on, a 35 Fluorescence, Rh-activatcd Al :03,(I 7s Ru/SiOr, hydrogenolysis of C2Hson, (r 34 Fuel Cells, NH,-O,, n 115 RuO?, polymethylene synthesis on, u 34 availabilitv of Pt for 48 RuO,, oxidation of cyclobutanols and catalysts ’ 21 aromatic rings on, a 34 H,-02, Pt clcctrodc in, a 74 Ru-Pd, deactivation of, by S-organic H,-Op, Pt/Ta and PtjC electrodes in, a 74 compounds, a 73 Ni electrodes. Pt-activated. a I53 Ru-Pt, hydrogenation of organic Ru-Pt electrodes in, a 153 compounds on, a 72 Furnaces, Rh-Pt elements for 86 Cathodic Protection, of salt water pipelines, a 153 Pb-Pt bielectrodes, in sea water 42 Gaspak-H, cell for ultra-purc H 15 Pd-Ti in chloride solutions 53 Glass, molten, Pt-clad equipment for 92 Crucibles, for crystal growing, a 70 Rh-Pt melting apparatus, a 75 Pt, for silicate analysis, a 32 vlscoslty of, a 15 Crystal Growth, garnct, a 70 wetting of, on Pt and Pt alloys, n 36 Electrical Contacts, Pd, alloys, contact Hydrogen, absorption on Pd alloys, a I09 resistance and wear of 122 ultra-purc 15 Pd, in telephone relays 14 Hydrogen Diffusion, in Ag-Pd cathodes 15 Pt metals, 4th International Symposium on 129 in Pd I07 Electrodepositiou of, Chromium, Pt metal Iridium, brittle fracture a deposits in, a 149 of, 146 coating on W, (1 70 Iridium. electrolvtes for. a 70 friction of 61 a ‘ on’w, 70 hot working of, n 68 Palladium, ductile, a 149 susceptibility of, temperature dcpcndence electrocrystallisation of, n 111 hard Cr plating by, a of, a 29 149 thermal expansion of, a I46 thick coatings 20 toughcns Fe-C alloys, a 31 Pd-Ni, composition, yield and physical vapour phase deposition of, on graphitc 62 properties of, a I12 Iridium Alloys, Iridium-Iron, activity in, a 147 Pd-Ag, from cyanide electrolytes, a 32 Iridium-Osmium, magnetic susceptibilities Platinum, hard Cr plating by, a 149 of, a 110 hardness of deDosits in. a 32 superconductivity, susceptibility and on cardiac pacemaker components, a 32 specific heat, in a 110 thick coatings 20 Pt Metal Allow. from bromide Iridium-Palladium, structure of, a 67 electrolytes,- a superconductivity, susceptibility and 1 I2 specific heat in, a 110 Pt-Re, hardness of deposits in, a 32 Iridium-Platinum, slit jaws, a 71 Rhodium, corrosion resistance on Ni of, n 149 superconductivity, susceptibility and Electrodes, Iridium, bright, 0, overvoltage on, a 149 specific heat of, a 110 reaction with 0,, a 70 thermal conductivity of, a 29 Rh and Ru surfaces, H, adsorption, (I 70 thermoelectric power of, a 109 Pb-Pt, for cathodic protection 42 Tridium-Plutonium, constitution diagram of, a 69 Nickel, Pt-activated, in fuel cells, a 153 Iridium-Rhenium, magnetic susceptibilities Osmium, Rh and Ru surfaces, H of, a 110 adsorption, a 70 superconductivity, susceptibility and Palladium, anodic behaviour of, a 111 specific heat of, a I10 microcoulomctry using, a 150 Iridium-Rhodium, superconductivity, reaction with 0,, a 70 susceptibility and specific heat of, a 110 Pd-Au, reduction of Oxat, a 31, 32 Iridium-Rhodium-Iron, magnetic transitions Platinum, adsorption of CsH I on, a 31 in, a 110 anode, perchlorate production on, a 148 Iridium-Ruthenium, superconductivity, anodic oxidation of CO on, a I48 susceptibility and specific heat of, (I 110 black, for NH,-0, fuel cell, a I14 Iridium-Sulphur, structure of, a 68 black, oxidation of CIH on, a 32 Iridium-Uranium, structure of, a I47 catalytic activity of, a 111 Iridium Bromide, preparation of, a 110 electrochemical activation of, a 70 Iridium Complexes, carbonyl halide, a 31 glass viscosity measured with, a 75 review of x-allyl, a 31 H atom-organic layer interaction, a 148 review of book on 47 in molten-carbonate fuel cell, a 74 Iridium Compounds, preparation of on C, Ta in fuel cells, a 74 thio-compounds, a 111 oxidation of CH,OH on, a I49 Iridium Hexafiuoride, oxidising properties of, a 148 platinised, oxidation of CHIOH on, a 70 Iridium Tetrafluoride, structure of, a 31 rate of H,-O, reaction on, a 148 Iridium Triiodide, thermal dissociation of, a 110 reaction with O,, a 70 surface area of, a 31 surface oxidation and reduction of, a 148 Janety, Marc Etienne, sales of Pt by 64 Pt-Au, reduction of 0, at, a 31, 32 Johnson Matthey, research, fifty years of 22 Pt Metals, in monolithic ceramic capacitors 46 Pt/Ti, anodes, for Ni- and Cr-plating, a 149 Laser Crystals, production of 16 anodes, in salt water pipelines, a 153 anodes, in sewage purification, a 153 Micromulometry, N1analysis by, a I50 Platinum Metals Rev., 1968, 12, (4) 162 Page Palladium Alloys (Contd.) Page Osmium, complexes, carbonyl halide, II 31 Palladium-Rhodium, H diffusion in 141 complexes, review of book on 47 thermoelectric power of, a 109 compounds, preparation of oxide Palladium-Rhodium-Iron, magnetic chlorides, a 111 transitions in, a I10 friction of 61 Palladium-Ruthenium, magnetic susceptibility of, temperature dependence wqceptlbilities of, a 110 of, a 29 Palladium-Silicon, electrical resistance of, a 30 Osmium Alloys, Osmium-Arsenic, viscosity of, a 67 decomposition of, a 69 Palladium-Silver, elcctrical contacts 122 Osmium-Iridium, magnetic susceptibilities electrical resistance of. a 30 of, a 110 thermal conductivity of, a 29 superconductivity, susceptibility and thermodynamic properties of, (1 109 specific heat of, a 110 thermoelectric Dower of. a 109 Osmium-Platinum, magnetic susceptibilities viscosity of, a 67 of, a 110 Palladium-Silver-Hydrogen, physical Osmium-Rhenium, magnetic susceptibilities properties of, a 30 of, a 110 Palladium-Silver-Tellurium, structure of, a 146 Osmium-Rhenium-Tungsten, preparation Palladium-Titanium, corrosion resistance of 53 and propertics of, a 30 structure of, a 109 Osmium-Selenium, decomposition of, a 69 Palladium-Vanadium, electrical contacts 122 Osmium Hexafluoride, oxidising propcrtics of, a 148 Palladium Oxide, cquilibria with rarc carths, n 147 Pallabraze, brazing alloys 105 Palladium Tetrafluoride, structurc of, a 31 Palladium, activator for W sintering, n 75 Platinum, black, surface-active cations on, a 148 complcxes, review of rr-ally], a 31 claddings for molten glass handling compounds, preparation of equipment 92 thio-compounds, a Ill complcxcs, rcvicw of x-allyl, n 31 diffusion of H, and D, in, a 67 compounds, preparation of thio- and diffusion of H, allotropes in 107 seleno-compounds, a Ill foils, study of, a 150 creep properties, at high temperatures 7 Lorcnz number at low temperatures, (1 67 crucibles, for silicate analysis, N 32 magnetic properties of, a 67 dcformcd, quciicliing or, a 108 review of book on 98 dispersion strengthened by carbides 7 susceptibility of, temperature depcndcncc electrical resistivity of, a 108 of, a 29 emitters for field ion microscopy, a 71 Young's modulus of, a 146 first rcfincrs, arsenic proccss of 142 Palladium Alloys, brazing with 105 high purity referencc standard 45 potentiomcter slidewires of 54 in stainless steel, corrosion protection 13 Palladium-Antimony, lattice parameters of, a 109 interaction with carbides, a 108 structure of, a 110 interdiffusion with refractory metals, a 108 Palladium-Boron, elcctrical resistance of, (I 30 microcrystals, a 29 Palladium-Cadmium, lattice parameters of, n I09 production and availability 48, 139 Palladium-Cerium, constitution of, a 30 Kaney, specific surface and activity of, a 148 Palladium-Chromium, electrical rcsistancc sales in the French revolution 64 of, u 30 smooth tips for field ion microscopy, n 149 structure of, a 30 specific heat of, a 108 viscosity of, a 61 suseentibilitv of. tcmnerature deoendcnce Palladium-Cobalt, thermodynamic of,'a 29 properties of, a I09 thermal conductivity of, a 108 Palladium-CoaDcr. thermodvnamic thermal diffusivitv of. 11 29 propcrties of, a' 108 toughens Fe-C alioys; u 31 Palladium-Deuterium, electrical resistivity vacancies in, cc 29, 108 of, a 146 wetting of glass 011, n 36 Palladium-Gold, brazing with, a 150 Platinum Alloys, potentiomctcr slidewires of 54 films, diffusion in, a 146 Platinum-Antimony, preparation and thick-film conductors 139 electrical properties of, a 108 Palladium-Gold-Mollbdenum, electrical Platinum-Arsenic, decomposition of, a 69 contacts 122 Platinum-Beryllium, wetting of glass on, a 36 Palladium-Hydrogen, ageing and cold Platinum-Cobalt, magnetic properties of, a 146 working of, a 30 structure of, a 29 electrical resistivity, of a 146 Platinum-Copper, heat of ordering of, Q 67 papcrs from Munstcr symposium on 140 thermodynamic properties of, a 108 Palladium-Hydrogen-Cold, absorption of Platinum-Dysprosium, magnetic properties H on,a 109 of, a 67 Palladium-Iridium, structure of, a 67 Platinum-Erbium, magnetic properties of, a 67 superconductivity, susceptibility and Platinum-Gadolinium, magnetic properties specific hcat of, a 110 of, a 67 Palladium-Iron, magnetic propcrtics Platinum-Gold, structure of, n 29 of, a 68, 109 therrnoclectric power of, a 109 structural transformations of, a I09 wetting of glass on, n 36 Palladium-Iron-Nickel, thermal expansion Platinum-Holmium, magnetic propcrtics of, a 147 of, a 67 Palladium-Iron-Nickel-Cobalt, thermal Platinum-Iridium, slit jaws, II 71 expansion of, a 147 Superconductivity, susceptibility and Palladium-Manganese, structure and specific hcat in, a 110 magnetic properties of, a 68 thermal conductivity of, a 29 Palladium-Nickel, enthalpy of formation of, thermoelectric power of, a 109 n 109 wctting of glass on, a 36 reaction of H, with. a 146 Platinum-Iron, magnctic slructure or, a 29 specific heat 0-f, a 109 Platinum-Mangancsc, structure and Palladium-Platinum, cnthalpy of formation magnetic propcrtics of, a 67 of. a 109 Platinum-Molybdenum, phase cquilibria in 134 thermoelectric power of, a 109 Platinum-Neodymium, magnctic propcrtics Palladium-Platinum-Iron, magnetic of, a 67 transitions in, a 68 Platinum-Nickel, enthalpy of formation of, a 109 Palladium-Platinum-Molvbdenum.strain Platinum-Osmium, magnetic susceptibility gauges 106 of, a 110 Palladium-Plutonium, constitution diagram Platinum-Palladium, enthalpy of formation of, a 69 of, (I 109 Platinum Metals Rev., 1968, 12, (4) 163 Platinum Alloys (Conrd.) Page Rhodium Alloys (Contd.) Page thermoelectric power of, a 109 Rhodium-Plutonium, constitution diagram Platinum-Palladium-Iron, magnetic of, a 69 transitions in, a 68 Rhodium-Ruthenium, magnetic susceptibility Platinum-Palladium-Molybdeuum, strain of, a I10 gauges 106 Rhodium-Selenium, structure of, a 68 Platinum-Plutonium, constitution diagram Rhodium-Sulphur, structurc of, a 68 of, a 69 Rhodium-Titanium. suoerconductivitv and Platinum-Praseodymium, magnetic specific heat of, b ~ 68 properties of, n 67 Rhodium-Titanium group metals, A ,B Platinum-Rhenium, magnetic susceptibility phases in, a 110 of, a 110 Rhodium-Uranium, structure of, a 147 Platinum-Rhodium, cladding for isotope Rhodium Bromide, structurc of, a 69 fuel capsule in space 88 Rhodium Carbide, dissociation of, a 69 crucibles for crystal growing, a 70 Rhodium Iodide, structure of, a 69 for glass melting, a 75 Rhodium Oxide, Rho,, rutile-type, a 147 furnace elements 86 Rhodium Tetrafluoride, structure of, a 31 interdiffusion with refractory Rustenhurg, increased output of platinum metals, a 108 from, 139 wetting of glass on, a 36 Ruthenium, complexes, carbonyl halide, a 31 Platinum-Terbium, magnetic properties of, a 67 complexes, formation of Platinum Carbide, dissociation of, a 69 [Ru(NHJsN,]? +, a Ill Platinum Hexafluoride, oxidising properties complexes, of N *, a 70 of, a 148 complexes, review of x-allyl, a 31 Platinum Metals, electrical contacts, 4th complexes, review of book on 47 International Symposium on I29 complexes, of triphenylphosphine with for laser crystal production 16 N, and H?, a Ill nitrosyl complexes 131 compounds, fixation of atmospheric N?by 111 organometallic chemistry of 89 foils, production and study of, a I50 semiconducting complexes, a 69 friction of 61 sulphates, properties of, a 147 resistor glazes for thick film circuits 99 susceptibility, temperature dependence susceptibility of, temperature dependence of, a 29 of, a 29 tertiary phosphine complexes 50 thermionic work function of, a 30 thermochemistry of 138 toughens Fe-C alloys 31 Platinum Oxide, gaseous, a 69 Ruthenium Alloys, Ruthenium-Iridium, PtO?. rutilc-tvtx. a 147 superconductivity, susceptibility and specific py roc hlore- type, .a 147 heat of, a I10 Platinum Silicide, in Schottky diodes 106 Ruthenium-Iron. thermodvnamic .~urouerties Platinum Tetrafluoride. structure of, u 31 of, a 68 Potentiometers, slidewire materials for 54 Ruthenium-Iron-Nickel, thermal expansion of, a 147 Research, Johnson Matthey, fifty ycars of 22 Ruthenium-Iron-Nickel-Cobalt, thermal Resistance Thermometers, Pt, at 2-10°K, a 36 expansion of, a 147 Pt, birdcage, a 36 Ruthenium-Molybdenum, magnetic Pt, calibration at 2-273.15"K, a 154 susceptibility of, a 110 Pt, miniature, calibration and stability Ruthenium-Niobium, magnetic of, a 154 Pt, scalc at 2-20°K, a I54 susceptibility of, a 110 Pt, self-hcating in 6 Ruthenium-Palladium, magnetic susceptibility of, a I lo Pt, temperature scales 11-273"K, a I I4 Ruthenium-Plutonium, conslit Lition diagram Resistors, glazes, Ru, for thick film circuits 99 of, a 69 Rhodium, coatings, wear behaviour of, a 112 Ruthenium-Rhodium, magnctic complexcs, olcfin, n 31 susceptibility of, a 110 complexes, review of ~-allyl,a 31 Ruthenium-Selenium, decomposi tion of, a 69 complexes, review of book on 47 Ruthenium-Uranium, intermetallic compound foils, study of, a 150 of, a 110 friction of 61 structure of, n 147 hot working of, a 68 interdiffusion with refractory metals, a 108 Ruthenium Bromide, crystal structurc of, a 110 Susceptibility of, temperature dependence Ruthenium Dioxide, and its hydrate, magnctic and electrical properties of, a 111 of, a 29 Ruthenium Oxide, RuO2-O2-RuO,equilibrium, a 147 toughens Fe-C alloys, a 31 Ruthenium Trichloride, structure of, a 31 Rhodium Alloys, Rhodium-Iridium, superconductivity, susccptibility and specific heat in, a 110 Schottky Diodes, Pt silicidc in 106 Rhodium-Iridium-Iron, magnetic transitions Semiconductors, metal complex, a 69 in, a 110 Space, Pt-clad isotope fuel capsu!e in 88 Rhodium-Iron, activity in, a 147 Steel, determination of C in 82 magnetic transitions in, a I10 Strain Gauges, high temperature I06 transformations in, a 30 Rhodium-Iron-Nickel, thermal expansion Telephones, Pd contacts in relays for 14 of, a 147 Thallium Platinatc, synthesis of, a 69 Rhodium-Iron-Nickel-Cobalt. thermal Thermocouples, Pallador I, Hall effect expansion of, a 147 Rhodium-Iron-Palladium, magnetic measured by, a 75 transitions in, a I10 Platinum: Rhodium-Platinum, accuracy Rhodium-Molybdenum, magnetic of, a 154 susceptibilities of, a 110 expendable cartridge 82 Rhodium-Palladium, H, diffusion in 141 in glass furnace, a 75 in X-ray furnaces, a I 54 thermoelectric power of, a 109 stability of, a 36 Rhodium-Palladium-Iron, magnetic Rhodium-Platinum. effect of clinker on transitions in, a 110 sheaths of, a 154 Rhodium-Platinum, cladding for isotope : fuel capsule in space 88 Rhodium-Platinum Rhodium-Platinum, protective casings for, a 154 crucibles for crystal growing, a 70 stability of. 36 for glass melting, a 75 a furnace elements 86 interdiffusion with refractory metals, a 108 Wollaston, W. H., lecture by 66 Platinum Metals Rev., 1968, 12, (4) 164