112 



L. F. Nilson, 



2. y 3 -Selenite: Sb 2 .0 G .3SeO+Se0 2 , 



after its digesting with 4 (analyses 1 — 2) and 10 (analyses 3 — 4) mol. 

 selenious acid, or, in other words, when diselenite and tetraselenite might 

 have been formed. After evaporating the solution at about 60° and 

 treating the residue with water, the salt was obtained in form of prisms, 

 discernible in the microscope, and generally of a laminar appearance. 



Analyses: 



1) 0.524 gr. salt gave 0.225 gr. selenium or 0.3161 gr. selenious acid. 



2) 0.507 gr. salt gave 0.221 gr. tetroxide of antimony or 0.2095 gr. trioxide. 



3) 0.6065 gr. salt gave 0.2555 gr. selenium or 0.359 gr. selenious acid. 



4) 0.512 gr. salt gave 0.221 gr- tetroxide of antimony or 0.2095 gr. trioxide. 



Calculated on 100 parts: 



experiment theory 



1. 2. 3. 4. 

 Oxide of antimony . — 41.32 — 40.92 Sb 2 3 292 39.68 

 Selenious acid . . . 60.32 — 59.19 — 4Se0 2 444 60.32 



736 100.00 



The above selenites of antimony have their correspondents in two 

 sulphates, examined by Peligot: *) 



Sb 2 .0 5 .2S0 2 

 Sb 2 .O fi .3S0 2 + H 2 .0 2 .S0 2 . 



Lastly I have examined selenites of three quadrivalent elements, 

 viz.: thorium, zirconium and tin, a description of which I now communicate. 



SELENITES OF THORIUM. 



1. Neutral: Th.0 4 .2SeO + 8H 2 0. 



Sulphate of thorium was precipitated with excess of selenite of so- 

 dium. The precipitate was very voluminous, and partly deposited very 

 slowly. Subjected to the microscope it exhibited only traces of a cry- 

 stalline form. Insoluble in water, it is readily dissolved in hydrochloric acid. 



') Ann. de chim. et de phys. [3] XX. p. 283. 



