Researches on the Salts of Selenious Acid. 



89 



The same salt was also obtained by treating- the neutral salt with 

 9 mol. or 128.73 pr. ct. selenious anhydride and, for the rest, proceeding 

 in the manner stated above. 



Analyses: 



1) 0.5045 gr. salt gave 0.2125 gr. selenium or 0.2986 gr. selenious acid 

 and 0.305 gr. sulphate of yttrium or 0.1483 gr. yttria. 



2) 0.4477 gr. salt gave 0.1885 gr. selenium or 0.2648 gr. selenious acid 

 and 0.269 gr. sulphate of yttrium or 0.1308 gr. yttria. 



These values are in 100 parts: 



Yttria 29.39 29.22 



Selenious acid. . . 59.19 59.15, 



numbers very closely agreeing with those calculated from the formula 

 given above. 



Yttrium seems consequently unable to form any salt more acid than 

 4 / 3 -selenite with selenious acid. The analogy with iron in this respect, 

 has just been pointed out. 



Cleve j ) obtained the same compound by passing newly-precipitated 

 hydrate of yttrium into selenious acid and precipitating the nitrate of 

 yttrium with acid selenite of sodium. 



SELENITES OF ERBIUM. 



1. Neutral: Er 3 .0 6 .3SeO + 5H 2 0. 



Nitrate of erbium, not being completely neutral, but holding free 

 nitric acid, when treated with excess of selenite of sodium, yielded a heavy 

 precipitate which, analogous to the above described selenite of yttrium, 

 was composed of microscopical, globular, transparent masses. 



Analyses: 



1) 0.6967 gr. salt gave 0.2094 gr. selenium or 0.2942 gr. selenious acid 

 and 0.5395 gr. sulphate of erbium or 0.3337 gr. erbia. On white- 



') Bih. t Sv. Vet. Ak:S handl. I N:o 8 s. 37. 

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



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