Chemistry and Physics. 325 



composition approaching that required for the supposed com- 

 pound AsCl 5 . It may be observed that there is very slight evi- 

 dence here that the liquid was a definite compound rather than a 

 solution of AsCl 3 in liquid chlorine, for there is no doubt that the 

 boiling point of chlorine would be raised appreciably by the 

 presence of a large amount of a substance in solution. However, 

 the authors state that the product after being dissolved in abso- 

 lute ether at —30°, gave yellow prisms when the solution was 

 chilled several degrees, and that a special preparation made in a 

 sealed tube formed beautiful yellow crystals at — 38 or 40°. 

 These facts furnish, perhaps, some evidence of the existence of 

 the pentachloride, but it seems unfortunate that the crystals were 

 not analyzed. — Jour. Amer. Chem. Soc, Nov., 1902. h. l. w. 



3. Electrolytic Peroxides of Lead, Nickel and Bismuth. — 

 Hollaed finds that when lead is deposited in the form of a 

 higher oxide by the electrolysis of nitric acid solutions of lead 

 nitrate, the deposit does not consist of pure lead dioxide as has 

 been supposed, but that it contains less lead than the amount 

 corresponding to this compound (which contains 86 '6 per cent of 

 lead). The variation is but slight with large deposits, such as 

 one containing 10 s of lead, but it is much greater with small 

 quantities. When about *01 g of lead was present, the deposit 

 contained 74 per cent of lead, and as the lead was increased in 

 quantity the amount of lead in the deposit gradually increased to 

 86-1 per cent for 10 g . The explanation is advanced that higher 

 oxides than Pb0 2 are formed, but this point does not appear to 

 be proven. 



A deposit of nickel oxide was obtained by electrolyzing an 

 alkaline pyrophosphate solution containing chromic acid. The 

 weight of the deposit corresponded to the formula Ni0 4 on the 

 assumption that nothing but nickel and oxygen was present, but 

 in this case also the point was not proven. An anodic deposit 

 from bismuth sulphate in nitric acid indicated the improbable 

 formula Bi 2 7 . — Comptes Pendus, cxxxvi, 229. h. l. w. 



4. A Peculiar Double Scdt of Silver Iodide. — Steomholm has 

 observed the remarkable fact that when solutions of tetraethyl- 

 ammonium iodide are treated with silver salts, the precipitates 

 are not yellow but white. This is caused by the formation of a 

 double salt N(C 2 H 5 ) 4 I*2AgI, which is distinguished from all the 

 previously known double salts of the silver halides, not only by 

 representing a new type, but by its great stability in dilute solu- 

 tions. Such double salts are usually stable only in contact with 

 very concentrated solutions of the soluble halides, hence the 

 tetraethyl-ammonium-silver iodide resembles the double cyanides 

 in its stability, although, unlike them, it is insoluble. The com- 

 pound under consideration can be washed with a 1^- per cent solu- 

 tion of iST(C 2 H & ) 4 I, but it is decomposed in contact with boiling 

 water with formation of yellow silver iodide. It is decomposed 

 also by warming with an excess of silver nitrate solution, with 

 the formation of the same yellow product. The double salt is 

 entirely stable when exposed to daylight. — Berichle, xxxvi, 142. 



H. L. W. 



