Samarium chloride, SmCl₃

Samarium chloride, SmCl₃, is a very pale yellow, hygroscopic, crystalline solid which darkens when heated and melts to a brown liquid.

From aqueous solution the hexahydrate, SmCl₃.6H₂O, separates in large, yellow tablets of density 2.383 (Cleve). The monohydrate, SmCl₃.H₂O, is also known. Samarium aurichloride, SmCl₃.AuCl₃.10H₂O, crystallises in orange prisms; the chloroplatinate has the formula 2(SmCl₃.PtCl₄).21H₂O.

Anhydrous samarium chloride absorbs ammonia. The following compounds are known, their dissociation pressures being 760 mm. at the temperatures given opposite the formulae: -

SmCl₃.NH₃ - 375° C.
SmCl₃.2NH₃ - 240° C.
SmCl₃.3NH₃ - 200° C.
SmCl₃.4NH₃ - 155° C.
SmCl₃.5NH₃ - 105° C.
SmCl₃.8NH₃ - 76° C.
SmCl₃.9.5NH₃ - 40° C.
SmCl₃.11.5NH₃ -15° C.
Curiously enough, a compound with 6NH₃ does not appear to exist.