[1] Univ Versailles St Quentin En Yvelines, Inst Lavoisier, CNRS, UMR 8180, F-78035 Versailles, France
[2] Univ Aix Marseille 1, MADIREL, CNRS, UMR 6121, F-13397 Marseille, France
[3] ENSICAEN Batiment C, Catalyse & Spectrochim Lab, CNRS, UMR 6506, F-14050 Caen, France
[4] Univ Montpellier 2, Inst Charles Gerhardt, CNRS UM2 ENSCM, UMR 5253, F-34095 Montpellier 5, France
[5] ESRF, SNBL, BP 220, F-38043 Grenoble, France
[6] Birkbeck Coll, Sch Crystallog, London WC1E 7HX, England
[7] UCL, Dept Chem, London WC1H 0AJ, England