BENEDICT. — DOUBLE SALTS OF ANTIMONY. 9 



11. 



CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE, UNDER THE DIRECTION OF 



PROFESSOR JOSIAH P. COOKE. 



DOUBLE HALOID SALTS OF ANTIMONY, CALCIUM, 



AND MAGNESIUM, WITH OBSERVATIONS ON 



THE REMARKABLE DISSOCIATION OF 



THESE COMPOUNDS. 



By Francis Gano Benedict, A. M- 



Presented by J. P. Cooke, May 9, 1894. 



In a recent paper,* we described the results of our study of the 

 double haloids of antimony and the alkaline metals. Since then we 

 have extended the investigation to the corrrespouding compounds 

 with calcium and magnesium, and, although the work is still in an 

 unfinished state, it must necessarily be interrupted for the present ; 

 and we therefore give here the results thus far obtained, the most 

 important of which is the complete dissociation of a definite crystalline 

 salt at the ordinary temperature of the air. 



In the paper referred to,t a salt was mentioned having the composi- 

 tion SbCls . 2 KCl . 2 HoO, and the difficulties encountered in its prep- 

 aration, analysis, and crystallographic study were discussed. Chief 

 among these difficulties was the circumstance that the water of crystal- 

 lization was lost wholly or in part at temperatures above — 5° Cent., 

 requiring the salt to be handled in a room below that temperature. 

 In dealing with these new compounds the necessity for cold weather 

 is even greater than in the case just mentioned. Hence the advancing 

 of the season has prevented further work on this line. The research 

 will be continued at the earliest opportunity. 



Poggiale,t in 1845, was the first investigator to obtain double 

 haloids of antimony and the earthy alkaline metals : " Le chlorure de 

 barium, uni au chlorure d'antimoine, presente una particularite qui 



* These Proceedings, XXIX. 212. % Comptes Rendus, XX. 1180. 



t Loc. cit. 



