Samarium. 27 



Orthophosphate of samarium 



SmPO^. 



This phosphate was obtained by dissolving the oxide of sama- 

 rium in melting metaphosphate of sodium. A topas-coloured glass was 

 thus produced which on cooling became enamel-like, owing to the formation 

 of small, but well formed, short prismatic crystals. The mass was trea- 

 ted with water, the crystals being thus obtained as a heavy crystalline 

 whitish yellow powder. The salt is scarcely attacked by boiling nitric 

 acid. In order to analyse it, the salt was decomposed by fusion with 

 soda. Some phosphoric acid always remains with the oxide of sama- 

 rium so it is quite indispensable to dissolve the oxide in nitric acid and 

 to precipitate with oxalic acid. 



0.7840 gram gave 0.5591 gram Sm^Og and 0.3311 gram MggPgOj. 



0.6114 gram gave 0.4354 gram SmaOg. 



0.3400 gram gave 2.5365 gram phosphomolybdate of ammonia. 



In percent: 



Calc 



Sm.Og 71.31 71.21 — 174 71.02 



P.Oj 27.01 — 27.83 71 28.98 



245 100.00 

 Spec. Grav: 



1.3611 gram, t° 17°.5, sp. Gr. 5.830 

 1.1194 » » » » » 5.826 



Mean of both determinations: 5.828. 

 Molecular volume: 42. 



Di-sodium-orthophosphate gives with nitrate of samarium a bulky 

 white, and amorphous precipitate which can only be washed with diffi- 

 culty and easily passes through the filter. When dried it forms white 

 hard pieces. The precipitate, dried in the air at ordinary temperature, 

 gave on analysis : 



0.4203 gram lost at 100° 0.0290 gram and in red-hot 0.0317 gram. 

 It gave, melted with carbonate of sodium, 0.2494 gram SmgOj and 0.1760 

 gram Mg,P,0,. 



