Researches on the Salts of Selenious Acid. 



33 



Analyses : 



1) 0.7948 gr. salt gave 0.4719 gr. selenium or 0.6631 gr. selenious acid 

 and . 1633 gr, sulphate of lithium or . 0445 gr. lithia. 



2) 0.8005 gr. salt gave 0.476 gr. selenium or 0.6688 gr. selenious acid 

 and 0.165 gr. sulphate of lithium or 0.045 gr. lithia. 



3) 0.6385 gr. salt did not diminish in weight by being kept in dry air; 

 at 100°, it speedily lost 0.023 gr. of its weight, and then gradually di- 

 minished, until the loss amounted to 0.037 gr. 



Centesimally represented : 



found calculated 



1. 2. 3. 



Lithia 5.60 5.62 — V 2 Li 2 15 5.68 



Selenious acid ... 83.43 83.53 — 2Se0 2 222 84.09 



Water (loss) .... 10.97 10.85 5.79 1V 2 H 2 27 10.23 



100.00 100.00 264 10CUX) 



The ascertained loss of weight at 100° makes a little more than 

 half the quantity of water that could have been parted with. Of the 5.79 

 pr. ct., 3 . 60 pr. ct. went off very speedily, the rest rather slowly. It seems 

 more than probable that, also from this salt, as is the case with the tetra- 

 selenites of potassium and sodium, 2 / 3 of the hydrogen may be expelled at 

 100°; the melted state of the salt, however, makes it considerably more 

 difficult to expel the water. 



SELENITES OF SILVER. 



Neutral: Ag 2 .0 2 .SeO. 



This is the only selenite of this metal; as being extremely difficult 

 to be dissolved, even in boiling water, it is easily obtained by double de- 

 composition or, since it is also dissoluble in dilute nitric acid, by treating 

 nitrate of silver with free selenious acid. It is also formed by direct com- 

 bination between oxide of silver and an excess of selenious acid, which 

 cannot dissolve it. The salt crystallizes in white, fine, needles and under- 

 goes no change on exposure to sun-light. After strong heating, pure, me- 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 5 



