J. Phys. IV France 7 (1997) C2-1051-C2-1056
In Situ EXAFS Characterisation of the Synthesis of Polynuclear Chloroniobates from Sm Atom Reactions with Niobium PentachlorideC. Den Auwer1, 2, 3, M. P. Andrews1, V. Briois2, C. Cartier dit Moulin2 and H. Dexpert2
1 Department of Chemistry, McGill University, Montreal Québec H3A 2K6, Canada
2 LURE, Université Paris Sud, 91405 Orsay Cedex, France
3 CEA ValRhô, DCC/DRDD/SEMP, 30207 Bagnols sur Cèze, France
A new method to prepare solid state chlorometallates by reductive dechlorination of solvated niobium pentachloride with vaporisation of nominally free atoms of samarium is described. Products were prepared in an original set-up by evaporation of samarium into a mixed toluene solution of NbCl5, at 180 K. The local order around the Nb atoms was probed by EXAFS spectroscopy at the Nb K edge, using an in situ cryostat coupled to the metal vapour oven, in order to better understand the condensation mechanisms. These in situ measurements confirm our previous ex situ EXAFS studies with solid state products obtained by Sm vaporisation : condensation of NbCl, by face-sharing octahedra.
© EDP Sciences 1997