Researches on the Salts of Selenious Acid. 



73 



Analyses: 



1) 0.83 gr. salt, treated with hydrochloric acid, gave an insoluble residue 

 of 0.0435 gr. selenium or 0.0611 gr. selenious acid, and, from the solu- 

 tion, 0.585 gr. mercuric sulphide or 0.5247 gr. mercurous oxide and 

 0.136 gr. selenium or O.iOll gr. selenious acid. 



2) 0.7555 gr. salt, immediately with hydrochloric acid, gave 0.04 gr. sele- 

 nium or 0.0562 gr. selenious acid, and, in the filtrate, O.532 gr. mer- 

 curic sulphide or 0.477 gr. mercurous oxide and 0.124 gr. selenium 

 or 0.1742 gr. selenious acid. 



Calculated on 100 parts: 



e xp e r i m e n t theory 



1. 2. 



Mercurous oxide ... 63.22 Go. 14 5Hg 2 2080 63.12 



Selenious acid .... 30.39 30. 50 9Se0 2 999 30.32 



Water (loss) 6.39 6.36 12H 2 216 6.56 



100.00 100.00 3295 100. 00 



The relation of the quantity of selenium, precipitated from the salt 

 with hydrochloric acid, to the dissolved quantity is as 1 to 3, the formula 

 for decomposition with hydrochloric acid requiring' the relation of 5 to 13: 



2(5Hg 2 O.9SeO 2 )4-40HCl = 20HgCl 2 + 20H 2 O + 13Se0 2 + 5Se. 



The relation arrived at agrees far better with a formula for a dise- 

 lenite, requiring this very relation of 1 to 3, but, for the rest, the analytical 

 values do not agree with such a mode of composition. The capability of 

 selenious acid to afford acid salts in the most various proportions, most 

 obvious within the next following group, makes it besides not at all doubt- 

 ful that the salt really has the assumed composition. 



To judge from the foregoing investigation, mercurous oxide seems 

 to have a very great tendency to form basic salts with selenious acid; 

 6 / 7 -selenite, under circumstances when neutral salt could have been formed, 

 afforded a still more basic compound, viz. 2 / 3 -selenite, and, when a disele- 

 nite could have been formed, gave 3 / 4 -selenite. This remarkable result can 

 be derived from no other cause, than that the added selenious acid dissol- 

 ved out part of the base and formed with it a very acid, soluble salt, the 

 basic compounds in question remaining. An acid salt was obtained only 

 in the case when a tetraselenite was to be expected. Among all the basic 

 oxides the compounds of which with selenious acid have been treated of 



Nova Acta Beg. Soc. Sc. Ups. Ser. HI. 10 



