62 MR. WILLIAM CARLETON WILLIAMS 



a similar reaction might occur with antimony, giving rise 

 to the missing oxychloride corresponding to the phos- 

 phorus compound above mentioned. 



The following investigation was undertaken at Dr. 

 Roscoe's request, with the view of elucidating the above 

 reaction, as no oxychlorides derived from the pentachloride 

 have as yet been described. 



A mixture of one molecule of antimony pentoxide 

 (prepared by heating the pentachloride with water) with 

 three molecules of the pentachloride was heated for some 

 hours in sealed tubes to 140 C. On opening the tube 

 after cooling, it was found to contain, besides unchanged 

 pentachloride and pentoxide, two distinct solid crystalline 

 compounds. When the pentoxide prepared by the action 

 of nitric acid on the metal is heated with the pentachloride 

 in a similar way, no oxychloride is formed. 



One of these compounds fuses at 85 C. to a clear yel- 

 lowish liquid, whilst the other, produced only in small 

 quantities, is found in minute yellowish crystals adhering 

 to the top of the tube ; and these fuse at a higher tempera- 

 ture. In order to obtain the first of these substances in 

 a pure state, it is sufficient to place the tube upright in a 

 vessel of water at 90 , with the empty end downwards ; 

 the fusible oxychloride then melts, and collects as a per- 

 fectly clear yellowish liquid ; after cooling, the tube is 

 opened ; and the small quantity of residual pentachloride 

 having been poured off, the solid mass is dried on a porous 

 plate over solid caustic potash in vacuo. The oxychloride 

 thus obtained is a perfectly white crystalline substance, 

 exceedingly hygroscopic, so that when exposed to the air 

 for a few minutes it becomes a pasty mass which rapidly 

 changes to a liquid, [t readily dissolves in an aqueous 

 solution of tartaric acid ; whilst it is decomposed by water, 

 and is perfectly insoluble in carbon disulphide. The melt- 

 ing-point of the substance is 85 C, as a mean of well- 



