Researches on the Salts of Selenious Acid. 



83 



Represented in 100 parts: 



found calculated 



1. 2. 3. 



Oxide of chromium 18.17 17.91 — GVO 2 513 18.41 



Selenious acid ... 52.90 53.59 — 4Se0 2 444 53.43 



Water (loss) . . . . 28.93 28.50 18.16 13H 2 234 28.16 



100.00 TOCKOO 831 100.00 



This salt, which is of great importance for the estimation of the 

 qvantivalence of the rare earth -metals, and for this purpose will be made 

 use of in the following-, loses at 100° 8 mol. of water out of 13 (calc. 

 17.33 pr. ct.) 



4. Va-Selenite: Cr 2 2 .3Se04-2H 2 .0 2 .SeO+7H 2 0. 



3 / 4 -selenite, treated in an aqueous solution with 156.65 pr. ct. its 

 weight of selenious anhydride, being the quantity sufficient to form a tetra- 

 selenite, dissolves only very incompletely in cold. When the mixture 

 had evaporated at a moderate heat — about 60° — there was obtained a 

 viscid green mass, which treated with water deposited a green, flaky, mi- 

 croscopically crystalline compound, and the mother-liquor behaved precisely 

 in the same manner, as that of the preceding salt. 



Analyses: 



1) 0.5825 gr. salt gave 0.2635 gr. selenium or 0.3702 gr. selenious acid 

 and 0.102 gr- oxide of chromium. 



2) 0.5497 gr. salt gave 0.2508 gr. selenium or 0.3524 gr. selenious acid 

 and 0.0965 gr. oxide of chromium. 



3) 1-0595 gr. salt parted at 100° with 0.1235 gr. water. 



In 100 parts: 



Oxide of chromium 

 Selenious acid . . . 

 Water (loss) . . . . 



foun d 



1. 2. 3. 

 17.51 17.56 — 



63.56 64.10 — 



18.93 18.34 11.66 



100.00 100.00 



cal culated 



CrO 2 153 17.58 

 5Se0 2 555' 63.80 

 9H 2 162 18.62 

 8~70 100.00 



