Researches on the Salts of Selenious Acid. 



63 



SELENITES OF ZINC. 



l. Neutral: Zn OlSeO + H 2 0. 



Solutions containing sulphate of zinc and selenite of potassium being- 

 mixed afforded an amorphous, flaky, white precipitate, which washed with 

 water considerably diminished and was partially transformed into a cry- 

 stalline state. The microscopical crystals were formed of small prisms 

 united in bundles. In order to make this transformation complete, the salt 

 was placed under water, without success, even after boiling. When the 

 compound could not by this means be brought to crystallization, I tried to 

 heat it, at the same time adding a small quantity of selenious acid, by 

 means of which the end was easily attained and a completely homogeneous 

 crystal-powder obtained. 



Analyses: 



1) 0.679 gr. salt gave 0.2525 gr. selenium = 0.3548 gr. selenious acid and 

 0.2625 gr. oxide of zinc. 



2) 0.6332 gr. salt gave 0.2355 gr. selenium = 0.3309 gr. selenious acid 

 and 0.2435 gr- oxide of zinc. 



3) 0.4975 gr. salt did not diminish in weight when heated to 100°. 



In 100 parts; 



found calculated 



1. 2. 



Oxide of zinc .... 38.73 38.66 ZnO 81 38.57 



Selenious acid .... 52.25 52.26 SeO 2 111 52.86 



Water (loss) 9.02 9^ H 2 _18 8.57 



100.00 lOChOO 210 100.00 



This salt is permanent both on exposure to the air and when heated 

 to 100°. 



2. Neutral: Zn.0 2 .SeO. 



The preceding salt heated with 52.86 pr. ct. anhydride of selenious 

 acid in water, gave a slightly yellow-coloured compound in small, four- 

 sided tablets. 



