68 



L. F. Nilson, 



5. Diselenite: Cd.0 2 .SeO + SeO 2 . 



When the neutral selenite of cadmium mentioned under 1 was di- 

 gested with 139.35 pr. ct. selenious anhydride, and the mixture had evapo- 

 rated to dryness at about 60°, it afforded, after treatment with water, a 

 salt insoluble therein in form of fine, microscopical, long prisms. 



Analyses: 



1) 0.772 gr. salt gave 0.4537 gr. sulphate of cadmium, corresponding to 

 0.2792 gr. oxide of cadmium, and 0.3466 gr. selenium or 0.487 gr. se- 

 lenious acid. 



2) 0.6435 gr. salt gave 0.3795 gr. sulphate of cadmium, corresponding to 

 0.2335 gr. oxide of cadmium; the selenium estimation was lost. 



Represented in 100 parts: 



found calculated 



1. 2. 



Oxide of cadmium .... 36.17 36.28 CdO 128 36 57 



Selenious acid 63.08 — 2Se0 2 _2_22_ ,63.43 



99.25 350 100.00 



Cadmium seems consequently to be deprived of the capability of 

 forming any salt with selenious acid, more acid than that now mentioned. 



SELENITES OF MERCURY. 

 A) MERCUROUS SELENITES. 



1. % -Selenite: Hg 6 .0 5 .2Se04 5H 2 = 2Hg 2 .0 2 .SeO + Hg 2 .0 + 5H 2 0. 



Mercurous nitrate was precipitated with an excess of selenite of 

 sodium. The obtained white precipitate proved when subjected to the mi- 

 croscope to be crystalline; when dried, it assumes a slightly yellowish 

 colour. On treatment with hydrochloric acid, as already Beezelius has 

 remarked, selenium partially separates and all the mercury is dissolved as 

 chloride. By the analysis, the selenium thus obtained was separately de- 

 termined, after which the filtrate was precipitated with hydrosulphuric acid. 



