Z Remsen — Phosphorus Oxychloride. 367 



The passage of ozone into the flask was continued for about 

 half an hour in the second experiment, and the product was 

 then examined. About three quarters of the liquid now boiled 

 above 100°, and it did not commence to boil below 85°. Bj 

 the iirst distillation it was thus separated into two parts, 

 one boiling below 100°, and the other boiling above 100°. The 

 latter, without further treatment, was at once analyzed. A 

 small quantity was weighed in a sealed bulb, and the bulb 

 then broken under water. After decomposition, pure nitric 

 acid was added and the solution then precipitated with silver 



0-251 grams of the substance gave 0-6842 grams AgCl = 

 1692 grams CI. 



This corresponds to 6741 per cent of chlorine, while phos- 

 phorus oxychloride contains 69-37 per cent of chlorine and the 

 trichloride 774 per cent chlorine. This analysis could hardly 

 be expected to give more satisfactory numbers, as very little 

 precaution was taken to separate the pure oxychloride from 

 the mixture. It proves, however, that the liquid under exami- 

 nation contains markedly less chlorine than the trichloride with 

 which we started, and nearly the same amount as the oxychlo- 

 ride which we would expect to be formed under the circum- 

 stances described. The deficit in chlorine may be accounted 

 for by considering the yellow resinous material, above referred 

 to, as being free from chlorine ; " ' ' 

 tile with the vapors of phosph( 



In addition to the above facts, it was found that the liquid 

 was decomposed slowly by cold water — much less readily than 

 the trichloride— and as a product of the decomposition with 

 water, a large amount of phosphoric acid was formed. Taking 

 then everything into consideration, there cannot be much doubt 

 that, when ozone acts upon phosphorus trichloride, the latter is 

 readily converted into the oxychloride. 



The reaction is analogous to those referred to above, viz: 

 the production of the oxychloride by the action of ox3^gen upon 

 boiling trichloride, and that of the sulphochloride by the action 

 of sulphur on the trichloride at 130°. Further, it is analogous 

 to the reaction which gives rise to the formation of phosphorus 

 perchloride by the action of chlorine upon the trichloride. 

 The most natural thought that suggests itself is that all these 

 bodies have a constitution similar to that of phosphorus per- 

 chloride, and that, in the above reactions, phosphorus passes 

 from the triad to the pentad condition. Those who hold the 

 view that the valence of an element is invariable are inclined 

 to consider phosphorus oxychloride as having a structure essen- 

 tially different from that "^ of the perchloride, and they write 

 its formula thus: 



