SOME NEW SALTS OF CADMIUM. 17 



From these experiments we may conclude that Iodide of Cadmium 

 combines with alkalic and earthy iodides in the proportion of equal 

 equivalents ; the formula? of the new compounds just described being 

 as follows : 



KI + CdI + 2HO 



NH 4 I + CdI + 2HO 



NaI + CdI + 6HO 



BaI + CdI + 5HO 



SrI + CdI + 8HO 



In this respect they partly correspond with, and partly differ from, 

 the Zinco-iodides described by Hammelsberg in Poggendorff 'a 

 Annalen, B. 43 ; the formulae of which are aa followa : 

 KI + 2 Znl 

 NIPI + Znl 

 NaI + ZnI + 3HO 

 BaI + 2 Znl 

 In analyzing the above mentioned cadmio-iodide8, the iodine was 

 first precipitated by nitrate of silver, the excess of silver aeparated 

 by hydrochloric acid, and the cadmium precipitated by sulphuretted 

 hydrogen, &c, &c. 



If we attempt to separate the cadmium at once as sulphide, we 

 meet with the difficulty alluded to by Stromeyer, viz., that iodide of 

 cadmium is decomposed very slowly by sulphuretted hydrogen. 



Some experiments were made to ascertain whether this difficulty 

 of decomposition is owing to the existence of a double salt of sulphide 

 with iodide of cadmium, but without any favorable results. 



Cadmio'bromide of Sodium. — This salt crystalizes from a mixture 

 of equal equivalents of the two bromides in small brilliant six-sided 

 plates, grouped together so as somewhat to resemble the analogous 

 double chloride. Owing however, to the small amount of bromine in 

 my possession, the quantity of salt obtained was but little, and the 

 crystals were not so free from an admixture of other salts as to yield 

 a satisfactory analyaia. 

 1.316 grma. gave 



Losa by heating 0.1465 = 11.13 Water. 



Sulphide of Cadmium. ..0.4219 = 24.93 Cadmium. 



Bromide of Silver 1.7355 = 56.13 Bromine. 



Sulphate of Soda 0.2750 = 6.76 Sodium. 



The numbera although not agreeing very well with tho calculation,, 

 seem to lead to the formula NaBr-f 2 Cd Br + 5 HO. 



B 



