Researches on the Salts of Selenious Acid. 61 

 Analyses: 



1) 1.0444 gr. salt gave 0.3554 gr. selenium = 0.4904 gr. selenious acid 

 and 0.3627 gr. oxide of copper. 



2) 1.0153 gr. salt gave 0.349 gr. selenium = 0.4904 gr. selenious acid and 

 0.3515 gr. oxide of copper. 



3) 0.5789 gr. did not change its weight in dry air and by heating at 100°. 



Calculated on 100 parts: 



experiment theory 



1. 2. 



Oxide of copper . 34.72 34.62 CuO 79.5 35. io 



Selenious acid . . 47.82 48.30 SeO 2 111.0 49.00 



Water (loss) . . . 17.4 6 17. 08 2H 2 36. Q 15.90 



100.00 100.00 226.5 100.00 



This compound is persistent both in ordinary and dry air and when 

 heated to 100°. Muspratt dried it over sulphuric acid and found it to 

 contain 3.18 — 3.42 pr. ct. water and 40.55 pr. ct. oxide of copper, without 

 mentioning the method used in either case. As he has produced selenite 

 of copper in the same manner as that here related, only with the difference 

 that selenite of ammonium has been used as a precipitant instead of sele- 

 nite of potassium, there can be no doubt that the salt, examined by him, 

 was identical with the above mentioned, that both his determinations are 

 erroneous and that there exists no such salt as the one, furnished by 

 him, viz. 3Cu.0 2 .SeO + H 2 0. 



2. Diselenite: Cu.0 2 .SeO+H 2 .0 3 .SeO + 2H 2 0. 



By mixing hydrate of copper with an aqueous solution of sele- 

 nious acid, there was obtained a gray- blue crystalline salt, which is 

 scarcely soluble in cold water but when boiled becomes green, probably 

 under decomposition. 



An aly sis: 



1.05 gr. salt gave 0.251 gr. oxide of copper and 0.456 gr. selenium = 

 0.6407 gr. selenious acid. 



