Researches on the Salts of Selenious Acid. 



25 



Centesimally represented : 



found calculated 



1. 2. 



Thallious oxide 79.22 79.06 TFO 424 79.25 



Selenious acid 19.32 19.43 SeO 2 111 20.75 



98 . 27 98.49 535 100.00 



2. Diselenite: TlH.OlSeO. 



This salt was obtained by means of double decomposition of sulphate 

 of thallium with the anhydrous salt of barium, Ba.0 2 .SeO -f SeO 2 , which 

 shall be hereafter described; it separates readily from an aqueous solution 

 in large, yellow, wax-shining, four-sided, possibly quadratic prisms, com- 

 bined with pyramid of another order, terminal face and other faces. It 

 dissolves very easily even in cold water. 



Analyses : 



1) 0.562 gr. salt gave 0.1332 gr. selenium or 0.1872 gr. selenious acid and 

 0.425 gr. sulphate or 0.3575 gr. thallious oxide. 



2) 0.5025 gr. salt gave 0.1174 gr. selenium or 0.165 gr. selenious acid and 

 0.38 gr. sulphate of thallium or 0.3197 gr. thallious oxide. 



Centesimally represented : 



found calculated 



1. 2. 



Thallious oxide . . 63.61 63.62 V 2 T1 2 212 63.86 



Selenious acid. . . 33.31 32.84 SeO 3 111 33.43 



Water (loss) .... ^3^ 3.54 V 2 H 2 _9 2.71 



100 ioo 100.00 332 100.00 



3. Tetraselenite : TlH.0 2 .SeO + H 2 .0 2 .SeO. 



By treating 1 mol. of the next preceding salt with 1 mol. selenious 

 anhydride, a solution was obtained which, when it had assumed such a con- 

 sistency that it was scarcely liquid, afforded this salt in very large, long, 

 probably monoclinic prisms, with predominant orthodiagonal end-faces and 

 the ends obliquely truncated on both sides. The compound is very soluble 

 in water and permanent in contact with the air. 



Nova Acta Reg. Soc. Sc. Ups. Ser. III. 4 



