Neodymium chloride, NdCl₃

Neodymium chloride, NdCl₃, is a hygroscopic, rose-coloured, crystalline mass of density 4.134 at 25° (Baxter and Chapin).

From aqueous solution the hexahydrate, NdCl₃.6H₂O, crystallises out in rose-coloured, monoclinic crystals of density 2.282 at 16.5°. The hexahydrate melts at 124°. One hundred parts of water dissolve 98.7 parts at 13°, 140.0 parts at 100° of the anhydrous chloride, the solution being in equilibrium with the hexahydrate. The concentrated aqueous solution dissolves neodymium oxalate on warming, and a neodymium oxalochloride crystallises out when the solution is cooled.

The monohydrate, NdCl₃.H₂O, is also known.

The anhydrous chloride forms the following compounds w ith ammonia, the dissociation temperature being given with each formula: -

NdCl₃.NH₃ - 360° C; NdCl₃.2NH₃ - 255° C; NdCl₃.4NH₃ - 157° C; NdCl₃.5NH₃ - 117° C; NdCl₃.8NH₃ - 79° C; NdCl₃.11NH₃ - 26° C; NdCl₃.12NH₃ - -10° C.