212 PROCEEDINGS OP THE AMERICAN ACADEMY. 



IX. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE, UNDER THE DIRECTION OF 



PROFESSOR J. P. COOKE. 



DOUBLE HALOIDS OF ANTIMONY AND POTASSIUM. 



By Francis Gano Benedict. 



Presented February 14, 1894. 



Of recent years an extended investigation of the nature and struc- 

 ture of the double haloids has been undertaken. The Rubidium and 

 Caesium compounds with antimonious chloride have received a good 

 deal of attention, but an examination of the literature relative to 

 this line of work shows marked variations in analyses as well as 

 formulae, ascribed to the several compounds resulting from the inter- 

 action of potassic chloride and antimonious chloride. 



Accordingly an investigation was commenced to determine accu- 

 rately the true nature of these salts, resulting in the preparation and 

 analysis of four compounds. 



The success of the research is greatly due to the direction and 

 timely suggestions of Professor Cooke. 



The first work that appears to have been done on these compounds 

 is that of Jacquelaine* and Poggiale.f 



In 1837 Jacquelaine t described a salt formed by the union of 

 SbCl 3 with 2 KC1 as crystallizing in oblique rhombic prisms. His 

 analysis is subjoined. 



Calculated. Found. 



CI 1106.5 46.0 46.3 



Sb 806.4 33.5 32.8 



K 489.9 20.4 20.2 



99.9 99.3 



In 1845 Poggiale § described two salts; i. e. one with 2 KC1 or 

 SbCl 3 . 2 KC1, and one with 3 KC1, or SbCl 3 . 3 KC1. The latter is 



* Ann. Cliim. Pliys., LXVI 129. J Loc. cit. 



t Comptes Rendus, XX. 1180. § Loc. cit. 



