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View Article Online / Journal Homepage / Table of Contents for this issue 2110 BALL AND ABRAM : BISMUTHINITRLTES. Published on 01 January 1913. Downloaded by Cornell University Library 30/06/2017 07:42:59. WXXJ V. --€?ismu t h initrit es. By WALTERCRAVEN BALL and HAROLDHELLING ABRAM. IN previous communications (T., 1905, 87, 761; 1909, 95, 2126; 1910, 97, 1408) one of the authors of the present paper has described several compounds of bismuth nitrite with the alkaline nitrites. These compounds were chiefly remarkable aa affording a method for the gravimetric estimation of sodium, and for its separation from potmsium, owing to the insolubility of msium sodium bismuthinitrite and the non-formation of the corresponding potassium salt (T., 1910, 97, 1408). As it is unusual to find such sharp differences in the behaviour of sodium and potassium salts, the present authors have investigated all the salts of this series which they have been able to obtain, in order to discover, if possible, other facts bearing on this difference in behaviour. The salts which have been obtained all fall into two groups, of which View Article Online BALL AND ABKAM : BlSMUTElINITRlTES. 2111 the general formula are respectively X,Bi(NO,), and X,YBi(N02),. In these formulae X represents any of the metals ammonium, potassium, rubidium, msium, and thallium, whilst Y stands for either lithium, sodium, or silver. There are thus possible five compounds of the X,Bi(NO,), series, or simple bismuthinitrites, and of these, four have been obtained, the attempts to obtain the ammonium salt having been 60 far unsuccessful owing to the great instability of concentrated solutions of ammonium nitrite in the presence of acid. Although the ammonium salt has not been obtained, bismuthinitrites of several organic nitrogenous bases, such as cocaine and brucine, can easily be prepared. Of the mixed bismuthinitrites of the general type X,YBi(NO,),, fifteen are possible; for each of the metals X might exist together in a compound with any of the three metals represented by Y. These compounds have all been obtained. Although many attempts have been made to prepare compounds, in the solid state, containing two metals of the X series together, or two metals of the Y series together, they have been entirely unsuccessful. The same remark applies to all the attempts the authors have made to obtain compounds in the solid condition, containing two atoms of a Y series metal with one atom of an element represented by X, or to prepare compounds having the formula Y,Bi(NO,),. The simple bismuthinitrites of sodium and of lithium probably exist in solution, for deep orange-coloured liquids result when bismuth nitrate is added to solutions of the nitrites of these metals, just as happens in the case of potassium nitrite or of rubidium nitrite. Whereas, however, the bismuthi- iiitrites of the two latter metals can be precipitated from their Published on 01 January 1913. Downloaded by Cornell University Library 30/06/2017 07:42:59. solutions, this cannot be done with lithium or sodium. The apparent impossibility of preparing mixed bismuthinitrites containing only metals of the X series, or of the Y series, is well shown by adding czesium nitrate to separate solutions of the nitrites of sodium and of potassium each containing bismuth. With the sodium solution there occurs an immediate precipitate of the mixed salt, sodium czesium bismuthinitrite, even when traces only of msiurn salt are added. With the potassium solution there is no apparent change until a large quantity of cmium has been added, when a precipitate of the simple wsium bismuthinitrite gradually settles. Again, silver nitrate, the nitrate of an element of the Y series, when added to a solution of sodium nitrite containing bismuth, produces no deposition of a mixed compound containing two elements of the Y series, but on the addition of a potassium solution, or of a solution of any of the metals of the X series, there is at once a precipitation of the mixed X-Ag salt. View Article Online 2 112 BALL AND ABRAM : BISMUTHINITRITES. This difference in behaviour between sodium and potassium, which, as above-mentioned, is sufficiently pronounced to form a method of separating them, is now to some extent explained; for potassium, being a metal of the X series, will not form a mixed bismuthinitrite with ciEsium, also a, metal of this series, whereas sodium, belonging to the Y series, will do so. As the caesium sodium salt is a very insoluble one, the metal can in this way be separated from potassium, collected, and weighed.* In a similar manner, cmium and rubidium may be separated from potassium,+ for on adding a mixture of salts of the three metals to a concentrated solution of sodium nitrite containing bismuth, the mixed bismuthinitrites of sodium with caesium, and of sodium with rubidium, will precipitate, being only very sparingly soluble, whilst the very soluble potassium sodium salt remains in solution. It seems, then, necessary, in order that a mixed bismuthinitrite should be capable of existence, that it should coxitain a metal of the isomorphous series, (NK,), K, Rb, Cs, T1, together with one belonging to the isomorphous series, Li, Na, Ag, the metal of the former series being present in the greater atomic proportion. A further series of five compounds exists, containing nickel in addition to a metal of the X series. These compounds are precipitated when a nickel salt is added to the solution of a nitrite of * Incidentally, this explains another fact noticed in studying the estimation of sodium as sodium cssium bismuthinitrite. The reagent used contained 30 grams of potassium nitrite, 3 grams of bismuth nitrate, and about 1.5 grams of cesium nitrate per 100 c.c., and produced a yellow precipitate of sodium cmium bismuthinitrite on the addition of traces of a sodium salt. When a reagent containing less potassium nitrite was made up, it was noticed that part of the cesium woulcl Published on 01 January 1913. Downloaded by Cornell University Library 30/06/2017 07:42:59. gradually deposit as czesiuni bismuthinitrite, more being thus precipitated the lower the concentration of the potassium nitrite. Conversely, when the reagent contained more than 30 grams of potassium nitrite per 100 c.c., it could hold more cesium salt without deposition of cesium bismuthinitrite. There would appear to be an equi- lihrium between the aniounts formed 6f the very soluble potassium bismuthiuitrite and of the relatively insoluble ctxsium bismutliinitrite, the concentration of thc latter, when high concentrations of potassium nitrite were used, failing to reach the value necessary for precipitation. Theso facts seem to render unlikely the existence, even in solution, of a potassium cesium bismuthinitrite. j. Cssiuni may also be separated from rubidium by taking advantage of the greater insolubility of the cesium sodium bismuthinitrite. Thus, if a mixture of' caesium and rubidium nitrates is added to a concentrated solution of potassium nitrite containing bismuth, and then a sodium salt gradually, the cssium sodium bismuthinitrite will precipitate with a very small concentration of sodium, whilst the rubidium will remain in solution until a much greater concentration of sodium is attained. One of the authors has used this method satisfactorily for separating cmium from an impure rubidium chloride obtained in the extraction of lithium. The separation has not been iuvestigated quantitatively, and some rubidium nmains in solution. View Article Online RALT, AND ARRAM : RISMUTHTNITRITES. 2113 auy of t,lieue metals, ill presence of bisluutll. The Y inetals do not appear to form any mixed compounds with nickel. The bismuthinitrites Tesemble the cobaltinitrih closely in formulae, colour, and solubility i’n many cases ; thus silver produces no precipitate with lithium or sodium cobaltinitrite, nor with sodium or lithium solutions containing bismuth (sodium and lithium bismuthinitrites), but on the addition of a salt of a metal of the X series the corresponding X-Ag cobaltinitrite or bismuthinitrite is precipitated as a yellow or red, crystalline powder. In preparing the bismuthinitrites, chlorides should be absent, or present in only very small amount ; otherwise bismuth oxychloride w ill precipitate. As the bismuthinitrites are all hydrolysed by water, in most cases rapidly, it is impossible, as a rule, to wash them. They are generally prepared by precipitation from a strong solution of a nitrite, and it is, in consequence, difficult to remove all traces of mother-liquor from the preparations. The most that can be done is to remove the mother liquor as completely as possible by the aid of the pump, and then to press the crystals on porous plates. The nearly dry crystals are then kept for some hours, under pressure, between sheets of filter paper. Fortunately, the salta are highly crystalline, which renders it easier to remove mother liquor, bat the difficulty of completely effecting this removal frequently shows itself slightly in the analyses; thus the thallous sodium salt, which is precipitated on adding a thallous salt to a strong solution of sodium nitrite containing bismuth, shows a rather too high percent- age of sodium. This effect on the analytical results is hardly evident in the case of the less soluble bismuthinitrites, such as the silver salts, for these can be precipitated from a less concentrated Published on 01 January 1913. Downloaded by Cornell University Library 30/06/2017 07:42:59. mother liquor, but is chiefly seen in those which are the most soluble. The proportions of the different salts used in the preparation of the various bismuthinitrites may, as a rule, be considerably varied, and those given are simply the amounts which the authors have found to yield good results. In a few cases, such as that of the potassium sodium bismuthinitrite, the salt is formed with difficulty, and the proportions given cannot be much departed from.

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