Researches on the Salts of Selenious Acid. 



71 



precipitated from the solution of chloride with hydrosulphuric acid and cal- 

 culated from the weight of the mercuric sulphide dried in a waterhath; 

 further that selenium has been partly reduced with sulphite of alkali, partly 

 precipitated as selenate of barium"'. 



The following- three salts were namely obtained from the last men- 

 tioned basic mercurous selenite, when 1, 8 and 22 mol. selenious acid 

 were added to it, the mixture subsequently digested and dried at about 

 60° and the residue treated with water: 



3. 2 / 3 -Selenite: Hg G .0\2SeO 4- 4H 2 = 2Hg 2 .0 2 .SeO + Hg 2 -r-4H 2 0. 



This compound was obtained in the above named manner, by trea- 

 ting the basic salt with 1 mol. or 3 pr. ct. selenious anhydride, in form 

 of a white powder, which the microscope showed to be crystalline. 



Analyses: 



1) 0.5065 gr. salt, treated with hydrochloric acid, gave 0.038 gr. selenium 

 or 0.0534 gr. selenious acid; in the filtrate from it 0.4545 gr. mercuric 

 sulphide = 0.4077 gr. mercurous oxide and 0.0125 gr. selenium or 

 0.0175 gr. selenious acid. 



2) 0.5975 gr. salt, treated with hydrochloric acid, gave 0.0443 gr, selenium 

 or 0.0622 gr. selenious acid; from the filtrate hydrosulphuric acid pre- 

 cipitated 0.5365 gr. mercuric sulphide = 0.481 mercurous oxide and 

 0.012 gr. selenium or 0.0169 gr. selenious acid. 



Calculated on 100 parts: 



experiment theory 



1. 2. 



Mercurous oxide. . . 80.49 80.50 3Hg 2 1248 80.93 



Selenious acid .... 13.99 13.24 2Se0 2 222 14.40 



Water (loss) 5.52 6.26 4H 2 72 4.67 



100.00 100.00 1542 TOO. 00 



The relation of the selenium obtained immediately to that subse- 

 quently obtained from the solution is nearly as 3 to 1, which is also re- 

 quired by the formula: 



2(Hg fi .O\2SeO) + 24HC1 = 12HgCl 2 -4- 12H 2 + 3Se + SeO 2 . 



