View Article Online / Journal Homepage / Table of Contents for this issue 340 ABSTRACTS OF CHEMICAL PAPERS. Published on 01 January 1900. Downloaded 29/10/2014 13:19:53. Inorganic Chemistry. Preparation and Properties of Anhydrous Perchloric Acid. By DANIELVORLANDER and RUDOLFVON SCHILLING(Annalen, 1900, 310, 369--380).-Anbydrous perchloric acid is prepared by distilling potassium perchlorate (50 grams) with 96-97.5 per cent. sulphuric acid (150-175 grams) under 50-70 rnm. pressure, and after re- moving chlorine dioxide by means of a current of air, redistill- ing the product under the same pressure. The anhydrous acid is colourless, boils at 39" under 56 mm. pressure, and has a sp. gr. 1.764 at 22'/4"; it remains liquid in a mixture of ether and solid carbon dioxide. It does not dissolve in carbon tetrachloride, with which it forms a green emulsion, which soon becomes brown, and evolves hydrogen chloride and phosgene ; chloroform, however, dis- solves it in every proportion, and on exposing the solution to air, crystals of the monohydrate separate, whilst phosphoric oxide produces a violent explosion, When a few C.C. of benzene are added to a drop or two of perchloric acid, heat is generated, and a brown pre- View Article Online INORGANIC CHEMISTRY. 34 1 cipitate is formed; equal volumes yield a green emulsion, which explodes. The spontaneous decomposition of arihydrous perchloric acid proceeds when the substance is protected from light and maintained at a low temperature ; samples of the purest acid, sealed in glass bulbs, become pale yellow in 2 or 3 days, then gradually brown, and after 3 or 4 weeks the bulbs are shattered by the pressure of the gases evolved in the decomposition. The authors discuss the action of more concentrated sulphuric acid, and of phosphoric and pyrophosphoric acids on potassium perchlorate. M. 0.F. Molecular Weight of Sulphur as Determined by the Boiling Point Method. By LOUISARONSTEIN and S. H. MEIHUIZEN(Chem. Centr., 1900, i, 392-393 ; from Arch. nSerZnnd. sci. exp. nat., [ ii], 3, 89-130).-1n solutions, sulphur is found so have a molecular weight corresponding with the formula S,, whether above or below its transi- tion and melting points. No importanco is to be attached to the molecular weight 64 obtained by Orndorff and Terrasse in disulphur dichloride (Abstr., 1896, ii, 358), since this solvent decomposes at its boiling point. J. C. P. Sulphur Perfluoride, sF6; a New Gas. By HENHIMOISSAN and PAULLEBEAU (Compt. rend., 1900, 130, 865--871).-When sulphur is introduced into a vessel containing fluorine, it immediately takes fire, and burns with a livid flame ; the product is gaseous, and consists of at least two compounds, for the mixture, although quite insoluble in water, partly dissolves in an aqueous solution of potassium hydroxide. When the fluorine is in excess, the product contains 80-90 per cent. of the insoluble constituent ; the inert gas appears, therefore, to be a perfluoride. Published on 01 January 1900. Downloaded 29/10/2014 13:19:53. The mixture of sulphur fluorides is liquefied by cooling to - SO0, freed from foreign gases by fractional distillation, treated with concen- trated potassium hydroxide solution, and finally dried over the fused alkali; the perfluoride thus obtained is freed from traces of nitrogen by liquefaction and fractionation, the latter gas passing off in the first portion of the distillate. Sulphur perjhoride, SF,, is a colourless, inodorous, tasteless, incom- bustible gas, which does not support combustion; it is very sparingly soluble in water, dissolving to a slightly greater extent in absolute alcohol ; when cooled to - 55", it solidifies to a white, crystalline mass, which melts and boils at slightly higher temperatures. The perfluoride is o very inert gas, resembling nitrogen more than sulphur chloride ; potassium hydroxide, whether fused or in alcoholic or aqueous solution, does not act on it, and it is not affected by lead chromate, copper oxide, silver, copper, phosphorus, arsenic, boron, silicon, or carbon, even at a red heat. Fluorine, and the halogens, zr.mmonia, and hydrogen chloride have no action on the gas, even at high temperatures. No change occurs when the gas is heated alone up to the fusing point of hard glass; at the temperature of the induction spark, however, it is partially decomposed, but even after prolonging the action for over 2 hours, 11 per cent. of the perfluoride remains unchanged, When View Article Online 342 ABSTRACTS OF CHEMICAL PAPERS. sparked in the presence of excess of hydrogen, the perfluoride is completely decomposed with the production of hydrogen sulphide and hydrogen fluoride; these compounds, acting on the glass of the con- tainiDg vessel, form a yellow solid, which consists of sulphur, silica, and hydrofluosilicic acid. A mixture of the perfluoride and oxygen, when strongly sparked, yields a brown, flocculent solid; one part by volume of the latter gas is absorbed, and the total contraction is two volumes ; when the current intensity is diminished, the reaction takes a digerent course, an oxyfluoride of sulphur being produced, which is less rapidly decomposed by water than thionyl fluoride. When the perfluoride is heated with sulphur vapour in a glass vessel, lower fluorides of sulphur are produced, and these act on the glass, forming silicon fluoride and sulphur dioxide; if the heating is pro- longed, the decomposition is complete. Selenium behaves in a similar manner, but the reaction is more complicated, a mixture of silicon fluoride and the dioxides of sulphur and selenium being obtained. Calcium and magnesium, when heated in the gas, are only super- ficially attacked ; boiling sodium, however, rapidly absorbs the per- fluoride, When the gas is heated with hydrogen sulphide, the follow- ing reaction takes place : XF, + 3H,S = 6HF + 45 ; the hydrogen fluoride immediately attacks the glass of the vessel, so that hydrofluosilicic and silicic acids are the ultimate products. The paper contains a description of the apparatus employed in pre- paring the mixed fluorides. G. T. M. Density and Analysis of Sulphur Perfluoride. By HENRI MOISSANand PAULLEBEAU (Compt. reqzd., 1900, 130, 984-98S).- The gaseous sulphur perfluoride (preceding abstract) has a sp. gr. 5.03 (air = 1) ; its analysis was effected by heating it with sodium vapour, a mixture of sodium sulphide and fluoride being thus obtained, and also by heating with sulphur in glass vessels, and measuring Published on 01 January 1900. Downloaded 29/10/2014 13:19:53. the volume of the silicon fluoride and sulphur dioxide produced. The perfluoride was also decomposed by heating with selenium. The results thus obtained are in close agreement with the formula SF,. N. L. Sulphuric Acid containing Seleniuni. By CHARLESF. SCHLAG- DENHAUFFEN and C. PAGEL(J. Pharz., 1900, [vi], 11, 261-262)- A large number of samples of so-called ('pure " sulphuric acid were found to contain selenium; a very delicate test for the latter consists in adding a fragment of codeine to 4 or 5 drops of the concentrated acid, when a green coloration is produced in the cold, which changes to bluish-green at 100'. W. A. D. Passage of Argon through Thin Films of Indiarubber. By LORDRAYLEIGH (Phil. Mccg., 1900, [v], 49, 220--221).-Air was allowed to diffwe into an indiarubber balloon, and the composition of the contents then determined; it was found that the argon now formed 1.93 per cent. of the argon and nitrogen, whilst corresponding per- centage for air itself mas 1.19. Argon, therefore, passes through india- rubber more readily than nitrogen, but not in such a degree as to render the process suitable for the concentration of argon from the atmosphere. L. M. J. View Article Online INORGANIC CHEMISTRY 343 Electrolysis of Alkali Chloride Solutions with a Diaphragm. By FRITZFOERSTER and F JORRE(Zeit. cmorg. Chem., 1900, 23, 158-21 9).-Theoretical considerations show that the yield of chlorine obtained in the electrolysis of neutral alkali chloride solutions will in general be less than the yield of alkali, so long as the existence of hypochlorite in the anode solution is possible (compare this vol., ii, 72). When a diaphragm is used, the nature of the process depends on three factors-the ordinary electrical conduction in the diaphragm, the diff u- sion, and the electrical endosmose. Experiments with a platino-iridium anode, in which the anode and cathode solutions were analysed after the electrolysis, showed that the total yield of alkali diminishes with increasing concentration of the alkali hydroxide. The yield of chlorine was found to be less than the yield of alkali, especially in the first stages of the electrolysis; the difference vanished later on when the chlorate and hydrogen chloride concentrations became appreciable. The chloride concentration, owing to the electrical endosmose, falls much more slowly in the cathode solution than in the anode solution. Analysis of the anode solution after electrolysis indicated the presence of free hypochlorous acid and alkali chlorate, but not of alkali hypochlorita. The proportion of oxygen liberated at the anode increases regularly with the progress of the electrolysis. When carbon anodes are used, the process of electrolysis is essentially the same ; the gas liberated at the anode contains carbon dioxide, and hydrogen chloride is found in the anode solution at a higher alkali chloride concentration than when platino-iridium anodes are used. Solutions of potassium chloride give a better current yield than those of sodium chloride; this is connected partly with the greater dissociation of the former salt, and the greater velocity of migration of the potassium ion. J. U. P. Published on 01 January 1900. Downloaded 29/10/2014 13:19:53. Production of Iodated Potassium and Ammonium Carnall- ites. By AUGUSTDE SCHULTEN(Bull. SOC.Chinz., 1900, [iii], 23, 158-159.