Researches on the Salts of Selenious Acid. 



55 



3. Diselenite: Mn.0 2 .SeO + SeO 2 . 



The preceding salt, being' treated with 55.5 pr. ct. anhydride of 

 selenious acid and heated with some water, was converted into a beautiful 

 rosy-coloured, heavy precipitate, forming microscopical, oblique, four-sided 

 tablets. 



Analyses: 



1) 0.6016 gr. salt gave 0.3165 gr. selenium or 0.4447 gr. selenious acid 

 and 0.3115 gr. sulphate of manganese or 0.1465 gr. manganous oxide. 



2) 0.5345 gr. salt gave 0.282 gr. selenium or 0.3962 gr. selenious acid 

 and 0.278 gr. sulphate of manganese or 0.1308 gr. manganous oxide. 



Centesimally represented 



found calculated 



1. 2. 



Manganous oxide .... 24.35 24.47 MnO 71 24.23 



Selenious acid 73_.92 74.13 2Se0 2 222 75.77 



98.27 98760 293 100.00 



The same anhydrous salt was also deposited from a solution, pre- 

 pared by treating the neutral selenite Mn.0 2 .SeO + H 2 with 165.5 pr. ct. 

 its weight of selenious anhydride, with a view to obtain a tetraselenite; the 

 evaporation was in this case spontaneous. 



Analyse s: 



1) 0.512 gr. salt gave 0.271 gr. selenium or 0.3808 gr. selenious acid and 

 0.2563 gr. sulphate of manganese or 0.1205 gr. manganous oxide. 



2) 0.4827 gr. salt gave 0.2558 gr. selenium or 0.3594 gr. selenious acid 

 and 0.244 gr. sulphate of manganese or 0.1147 gr. manganous oxide. 



In 100 parts: 



1. 2. 



Manganous oxide . . . . 23.54 23.77 



Selenious acid 74.38 74.46 



97.92 98.23 



numbers leading to the formula above. 



No tetraselenite of manganese is consequently formed either at ordi- 

 nary or at higher temperatures. 



