Samarium. 19 



Selenates of samarium. 



I. Snij 3Se04 + 8H2 0. This salt crystallises from a very con- 

 centrated solution, on evaporating over oil of vitriol at 18", in small 

 sulphur-yellow crystals. The selenate is very soluble ; it loses scarcely 

 any water at 100°, but it becomes anhydrous at 280°. 



1. 0.9881 gram lost on careful heating over open fire 0.1642 gram 

 and left on heating to a white-heat, 0.3951 gram SmsOj. 



2. a. 0.6223 gram, decomposed with boiling hydrochloric acid 

 and treated with sulfurons acid, gave 0.1679 gram Se. From the filtrate 

 0.2457 gram Sra^Og was thrown down with oxalic acid. 



b. 0.8165 gram lost by 280° 0.1330 gram HjO. 



In percent: 



I II. C ale 



SrajO, 39.99 39.48 348 39.86 



SeOg — 43.37 381 43.64 



H,0 16.62 16.29 144 16.50 



873 100.00 



The selenate of samarium does not give any compound with 

 selenate of sodium. On spontaneous evoporation of the mixed solutions 

 one gets crystals of selenate of samarium. 



Spec. Grav. of the crystallised salt: 



1.3973 gram, crushed crystals, t° 13° sp. Gr. 3.326 

 1.2697 y> » » » » » 1> 3.329 



Mean of both determinations: 3.327. 

 Molecular volume: 262.4. 



II. Sm23Se04+ 12HjO. It crystallises at about 10° in yellow 

 brillant beautiful prisms which alter rapidly in the air. 



0.4915 gram lost by 100° 0.1204 gram HjO and by 230° 0.0850 

 gram. By ignition 0.3549 gram Sm^Og was obtained. 



1.5643 gram lost by 230° U.:^425 gram H.^O. 



