Changes of vibrational modes upon melting solid Cs2NaScCl6, Cs3ScCl6, Cs3Sc2Cl9 and ScCl3

Raman spectra of Cs2NaScCl6, Cs3ScCl6, Cs3Sc2Cl9 and ScCl3 compounds have been measured from 25 degrees C to temperatures above their melting points. The vibrational modes of the discrete species ScCl63- and Sc2Cl93- in the solids are transferred upon melting into the liquid and participate in an equilibrium involving ScCl4-. The spectra of solid ScCl3 are dominated by the vibrational modes of a triple layer of ions consisting of edge-sharing ScCl63- octahedra. Two main bands are seen in the melt spectra which infer a molecular liquid but a rather complex melt structure is suggested by the overall physicochemical data. (C) 1999 Elsevier Science B.V. All rights reserved.