Researches on the Salts of Selenious Acid. 



75 



Calculated on 100 parts: 



experiment theory 



1. 2. 



Mercuric oxide . . 61.67 62.37 HgO 216 62.61 



Selenious acid . . 31.44 31.89 SeO 2 111 32.17 



Water (loss) . . .'_ 6.89 5.74 H 2 18 5.22 



100.00 100.00 345 100.00 



The formation of this salt in presence of an excess of selenious 

 acid, without the mother-liquor containing any mercuric oxide, disproved the 

 existence of the soluble diselenite which Berzelius states himself to have 

 obtained. Nevertheless, the comportment of the neutral salt, when digested 

 with 1 and 3 mol. selenious acid under the circumstances so often men- 

 tioned above, was examined; I then obtained, in both cases: 



2. A-Seleiiile: 4Hg.Q 2 .SeO + H 2 .0 2 .SeO + 2H 2 0. 



crystallized in fine microscopical needles. 



Analysis 1) refers to the salt which was obtained, when 1 mol. sele- 

 nious acid was added, analysis 2), when 3 mol. were added. 



Analyses: 



1) 0.687 gr. salt gave 0.4335 gr. mercuric sulphide or 0.4035 gr. mer- 

 curic oxide and 0.1805 gr. selenium or 0.2536 gr. selenious acid. 



2) 0.697 gr. salt gave 0.443 gr. mercuric sulphide or 0.4124 gr. mercuric 

 oxide and 0.185 gr. selenium or 0.2599 gr. selenious acid. 



Calculated on 100 parts: 



experiment theory 



1. 2. 



Mercuric oxide. . . . 58.73 59.17 4HgO 864 58.66 



Selenious acid .... 36.91 37.29 5Se0 2 555 37.68 



Water (loss) 4^36 3.54 3H 2 54 3.66 



100.00 100.00 1473 100.00 



It seems consequently, that no salt, more acid than that now men- 

 tioned, is to be obtained; certainly, no diselenite is formed under the afore- 

 said circumstances. Berzelius, however, describes such a compound so 

 distinctly, that it cannot be doubted that he has really obtained a soluble 

 salt of mercuric oxide, formed "when selenious acid was saturated with 



