Researches on tee Salts of Selenious Acid. 



59 



In 100 parts: 



found calculated 



Oxide of nickel ... 33.13 NiO 75 33.79 



Selenious acid .... 49.21 SeO 2 111 50.00 



Water 17.66 2H 2 36 J 6. 21 



100.00 222 HHhOO 



Neutral salt of nickel, precipitated with selenite of sodium, affords 

 an amorphous, yellow-green salt, which on heating becomes crystalline; it 

 is undoubtedly of the composition now stated. 



2. Diselenite: Ni.0 2 .SeO + H 2 .0 2 .SeO + 2H 2 0. 



The neutral salt, dissolved in free acid and evaporated at ordinary 

 temperature, only gave a green gummy mass. By employing neutral salt 

 in excess, there was obtained a solution, which, on slowly evaporating in 

 a low vessel covered with a watch-glass, deposited a magnificently emerald 

 salt in microscopic, four-sided, in all probability quadratic prisms with ter- 

 minal faces. Permanent in the air, the salt at 100° loses part of its water. 

 It is but slowly soluble in water. 



Analyses: 



1) 0.635 gr. salt gave 0.2868 gr. selenium = 0.403 gr. selenious acid and 

 0.1348 gr. oxide of nickel. 



2) 0.4942 gr. salt gave 0.2223 gr. selenium = 0.3124 gr. selenious acid 

 and 0.105 gr. oxide of nickel. 



3) 0.3385 gr. salt, kept over sulphuric acid, did not diminish in weight, 

 but, heated at 100°, lost 0.0132 gr. water. 



In 100 parts: 



found calculated 

 1. 2. 



Oxide of nickel .... 21.23 21.25 NiO 75 21.37 



Selenious acid 63.46 63.22 2Se0 2 222 63.25 



Water (loss) 15,31 15.53 3H 2 54 15.38 



lOoToo 100.00 351 100.00 



3. Tetraselenite : Ni.0 2 .SeO + 3Se0 2 + H 2 0. 



By employing a large excess of selenious acid, and proceeding in 

 other respects in the same manner as in the preceding case, there is obtai- 



