Researches on the Salts of Selenious Acid. 



91 



3. Vs -Selenite: Er 2 .0 6 .3SeO + H 2 .0 2 .SeO + 3H 2 0. 



Under the same circumstances as the selenite of yttrium — i. e. by 

 digesting the neutral salt with three and nine mol. of selenious anhydride 

 at a temperature of 60° — selenite of erbium has also given a 4 / 3 -selenite, 

 nor does it seem capable of taking up more acid, analogous, in this, re- 

 spect, to the ferric and yttrium-salts. When the mixture had evaporated 

 to dryness and then been treated with water, there was in both cases 

 obtained an insoluble, microscopically crystalline powder, composed of 

 small prisms. 



Analyses: 



1) 0.5085 gr. salt gave 0.1772 gr. selenium or 0.249 gr. selenious acid 

 and 0.3407 gr. sulphate of erbium or 0.2107 gr. erbia. 



2) 0.5 gr. salt gave 0.175 gr. selenium or 0.2459 gr. selenious acid and 

 0.333 gr. sulphate of erbium, containing 0.206 gr. erbia. 



3) 0.781 gr. salt gave 0.2765 gr. selenium or 0.3885 gr. selenious acid 

 and 0.5092 gr. sulphate of erbium, corresponding to 0.3149 gr. erbia. 



Calculated on 100 parts: 



experiment theory 



1. 2. 3. 



Erbia 41.44 41.20 40.32 Er 2 0* 389 42.98 



Selenious acid . . 48.97 49.18 49.74 4Se0 2 444 49.06 



Water (loss). . . . 9-59 9.62 9.94 4H 2 _J2 7.96 



100.00 100.00 100.00 905 100.00 



The material for the analyses 1) and 2) was obtained by treating 

 the neutral selenite of erbium with 3 mol., the material for the analysis 3) 

 by treating it with 9 mol. selenious acid. 



Hoglund *) has examined the same salt, obtained by the action of 

 free selenious acid on a solution of nitrate of erbium, with or without addi- 

 tion of ammonia, until a permanent precipitate began to be formed. 



') Bih. t. Sv. Vet. Akad:s handl. I. N:o 8 s. 38. 



* 



