Researches on the Salts of Selenious Acid. 



21 



2) 0.806 gr. salt gave 0.354 gr. selenium or 0.4 ( J74 gr. selenious acid. 



3) 0.74 gr. salt gave 0.4315 gr. sal-ammoniac or 0.2099 gr. oxide of am- 

 monium. 



4) 0.7262 gr. salt gave 0.413 gr. *al-ammoniac or 0.2009 gr. oxide of 

 ammonium. 



Calculated on 100 parts: 



1. 2. 3. 4. 



Oxide of ammonium — — 28.36 27.67 



Selenious acid 60.78 61.73 — — 



numbers" closely agreeing with the formula above. 



If, on the contrary, this salt, in one or the other form, be taken up 

 from the mother-liquor and desiccated by pressing, it gives off ammonia 

 and smells strongly of it. On this account, it suffers a considerable loss 

 of weight, when it is kept in contact with the air, and then speedily deli- 

 quesces. If such a liquid, obtained by spontaneous deliquescence, when no 

 longer emitting any smell of ammonia, be allowed to crystallize over 

 sulphuric acid, it affords the residue of the neutral salt in form of mono- 

 clinic, four-sided prisms with basal end-faces, a crystalline form, characte- 

 ristic for the diselenite mentioned below. It was also proved by the ana- 

 lysis of the product, that this salt had been formed, for 



1) 0.531 gr. salt gave 0.2892 gr. selenium or 0.4063 gr. selenious acid or, 

 in 100 parts, 76.52 (required 76.03). 



2) 1.268 gr. salt gave 0.465 gr. sal-ammoniac or 0.2262 gr. oxide of am- 

 monium or 17.84 pr. ct. (required 17.81)- 



2. Sesquiselenite : 2Am 2 .0 2 .SeO + H 2 .0 2 .SeO. 



This salt was obtained, in the manner already accounted for, in very 

 well developed (monoclinic?) prisms Avith basal end-faces and hemidoma. 

 The crystals often reach a considerable length, 30 m. m. and more. They 

 are transparent, shining and deliquescent on exposure to the air. 



Analyses: 



1) 0.5155 gr. salt gave 0.2491 gr. sal-ammoniac or 0.1211 gr. oxide of 

 ammonium and 0.262 gr. selenium or 0.3681 gr. selenious acid. 



2) 0.5983 gr. salt gave 0.2851 gr. sal-ammoniac or 0.1387 gr. oxide of 

 ammonium and 0.308 gr. selenium or O.4328 gr. selonious acid. 



