Researches on the Salts of Selenious Acid. 



93 



Represented in 100 parts: 



found calculated 



1. 2. 



Oxide of eerium . 36.09 37.17 Ce 2 ;1 324 37. n 



Selenious acid . . 37.55 37.68 3Se0 2 333 38.14 



Water (loss) . . . 26.30 25 15 12H 2 216 24.75 



100.00 100. oo 873 100.00 



Jolin *), by precipitating- acetate of cerium with free selenious acid, 

 obtained an amorphous, neutral salt with 3 mol water, of which one half 

 was lost at 100°. 



3. y 3 -Selenite: Ce 2 .0 G .3SeO + H 2 .0 2 .SeO r-5H 2 0. 



This salt, produced in the above mentioned manner, afforded a mi- 

 croscopically crystalline, insoluble powder, the crystals being' gathered to- 

 gether into almost globular aggregates. 



Analysis: 



0.58 gr. salt gave 0.2065 gr. selenium or 0.2001 gr. selenious acid and 

 0.3807 gr. sulphate of cerium or 0.2187 gr. oxide of cerium. 



In 100 parts: 



found calculated 



Oxide of cerium ... 37.71 Ce 2 3 324 36.99 



Selenious acid .... 50.02 4Se0" 444 50.68 



Water (loss) 12.27 6H 2 108 12.33 



100.00 876 100.00 



By treating neutral salt with selenious acid, Jolin 2 ) obtained also 

 such an acid salt, but containing only 4 mol. water of crystallization. 



4. Diselenite : Ce 2 .O fi .3SeO. ■+ 3H 2 .0 2 .SeO + 2H 2 0. 



The basic selenite of cerium treated with 19 mol. selenious anhy- 

 dride and water at a moderate heat, atforded this salt well crystallized in 

 oblique, four-sided, microscopical laminae, not altering in water. 



Analysis: 



0.8155 gr. salt gave 0.3575 gr. selenium or 0.5023 gr. selenious acid and 

 0.429 gr. sulphate of cerium, containing 0.2465 gr. oxide of cerium. 



') Bull, soc chim. [2] XXI. p. 539. 

 2 ) Loc. cit. 



