Physicochemical and spectral investigations into neodymium complexing in the NdCl3 - AlCl3 system

The DTA techniques alongside with the visual-polythermal method have been used in studying the diagram of system NdCl3- AlCl3, revealing the formation of an incongruently melting, at 235 deg C, compound NdCl3 x AlCl3. A spectral study of the system samples has provided additional proof of formation of a compound in which the closest environment of the neodymium ion is different, as compared to NdCl3. In transition from NdCl3 to NdCl3 x AlCl3, the intensity of absorption of Nd3+ in NdCl3 decreases to the noise level, while the intensity of Nd3+ in NdCl3 x AlCl3 increases inversely. The Stark splittings of the neodymium ion levels in NdCl3 and NdCl3 x AlCl 3 are different, which is indicative of the formation of a new closest environment of the neodymium ion, accompanied by a change in the local symmetry and, probably, a change in the coordination number