[291] Compt. rend. 1900, 130, 1185.
[292] Ibid. 1904, 138, 84 and 1166.
[293] Eberhard, Zeitsch. anorg. Chem. 1905, 45, 374.
[294] Trans. Chem. Soc. 1883, 43, 362; Bull. Soc. Chim. 1885, [ii.], 43, 53; Chem. News, 1886, 53, 30, 45, 67, 80, 91, 100.
The melting-point of the metal lies between 1300° and 1400°C., so that its preparation by the electrolytic method is a matter of great difficulty. A mixture of the chloride with one-third of its weight of barium chloride is electrolysed by means of a current of 100 ampères, using a cathode of only 2·5 mm. thickness; the metal so obtained is greyish white in colour, and is the hardest of the cerium elements.
The chloride separates from aqueous solution as the hexahydrate, SaCl₃,H₂O, in large tabular yellow crystals. The anhydrous chloride is white, but fuses to a chocolate-brown liquid; it forms a large number of additive compounds with ammonia. When heated in an atmosphere of dry hydrogen or ammonia, air and moisture being carefully excluded, it yields the subchloride,[295] SaCl₂, as a dark brown crystalline solid, insoluble in alcohol and all organic solvents. Samarous chloride dissolves in water, forming a deep brownish-red solution, which rapidly becomes colourless, with evolution of hydrogen, and precipitation of the oxide and oxychloride. Samarous iodide, SaI₂, may be obtained by a similar process, and closely resembles the chloride.
[295] Matignon and Cazes, Compt. rend. 1906, 142, 83.
The bromate, Sa(BrO₃)₃,9H₂O, melts at 75°, and closely resembles the corresponding compounds of the didymium metals. The sulphate crystallises with 8, and the nitrate with 6 molecules of water. The carbonate, Sa₂(CO₃)₃,3H₂O, can be obtained only by passing carbon dioxide through an aqueous suspension of the hydroxide; addition of alkali carbonate to a solution of a samarium salt precipitates hydrated double carbonates.
The acetylacetone compound melts at 146°-147°C.
Many organic salts have been prepared by James, Hoben, and Robinson (loc. cit.).