Researches on the Salts of Selenius Acid. 



15 



SELENITES OF RUBIDIUM 



have hitherto not been investigated. As was to be expected, they exhibit 

 a complete analogy to the salts of potassium. 



1. Neutral: Rb 2 .0 2 .SeO + H 2 Q. 



This salt, with the greatest difficulty, separates from a syrupy solution, 

 prepared from carbonate and selenious acid in corresponding molecules, and 

 is obtained in microscopical crystals of a prismatic appearance, united in 

 groups and with the ends ensiformly pointed; most of them are there fur- 

 nished with an angle directed inwards. The salt is so extremely deliquescent 

 that, even under the receiver of the air-pump, it was very difficult to obtain 

 it in a fit state for analysis. It was desiccated, as well as possible, be- 

 tween folds of bibulous paper; the analysis indicated that by this treatment 

 and whilst weighed, it had absorbed a not inconsiderable quantity of water. 



Analyses: 



1) 0.936 gr: salt gave 0.221 gr. selenium or 0.3105 gr. selenious acid and 

 0.7665 gr. sulphate of rubidium or 0.5367 gr. rubidia. 



2) 0.4175 gr. salt gave 0.098 gr. selenium or 0. 1377 gr. selenious acid and 

 0.337 gr. sulphate of rubidium or 0.2359 gr. rubidia. 



Centesimally represented: 



found calculated 



1. 2. 



Rubidia 57.34 56.50 Rb 2 186.8 59.15 



Selenious acid . . 33.18 32.98 SeO 2 111.0 35.15 



Water (loss) . . . 9.48 1 52 H 2 18. 5.70 



100.00 100.00 315.8 100.00 



The less close correspondence between found and calculated values 

 is a consequence of the extreme deliquescence of the salt; this, however, 

 does not render its composition in the least doubtful. 



2. IMselenite: RbH.0 2 .SeO. 



When the solution has evaporated down to a syrupy mass, this salt 

 is obtained in oblique, four-sided prisms with basal end-faces; they have 



