OF ARTS AND SCIENCES. Ill 



Analysis op Antimonious Oxichloride (Sb^O^Clj). 

 Crystallized from a Tartaric-Acid Solution. 



100. 100. 



"We also determined the specific gravity of these same crystals ; which 

 we found to be, at the ordinary temperature, 5.014. 



Oxichloride of Antimony (SbgOjiCl^). 



As is well known, precipitated oxichloride of antimony (powder of 

 Algaroth), when washed with hot water, undergoes a gradual decompo- 

 sition ; yielding after long-continued washing pure antimonious oxide, 

 and hydrochloric acid, which is removed by the water. It is also 

 known that, if the snow-white bulky precipitate is left under the liquid 

 for a few days, it forms a grayish white mass, consisting of brilliant 

 microscopic crystals, which are described by Johnston and Miller as ob- 

 lique, rectangular prisms, having the obtuse summits replaced by planes. 

 The amorphous precipitate is undoubtedly a mixture of the two com- 

 pounds we have just studied, in varying proportions, depending on the 

 conditions of the precipitation ; but the crystals are evidently Sb^O^Cl,. 

 Johnston's analysis gives the exact theoretical per cent of chlorine 

 (11.25) ; and the mean of two analyses by Peligot gives the same.* 

 We can find no satisfactory evidence of a definite compound between 

 SbOCl and Sb^05Cl2 ; and the fact that, when gradually heated, SbOCl 

 manifests but one stage in its decomposition, seems to indicate that 

 such a compound cannot exist. We have carefully studied this decom- 

 position, and we would refer to the description of the phenomena 

 which we gave in our previous paper, page QS, of this volume.f There 



* Gmelin's Hand-book of Chemistry, Cavendish edition, iv. 367. 



t The decomposition of the antimonious oxichlorides by heat, after the 

 manner we have previously described, affords the finest crystals of Sb.,08 we 

 have ever seen. These crystals are in part brilliant octahedrons (Seuarmontite), 

 but chietly orthorhombic prisms (Valentinite). The last are frequently highly 

 modified, and terminated at both ends ; affording an opportunity for a more com- 

 plete crystallographic investigation of this substance. 



