[1] Univ Nancy 1, Fac Sci, Lab Cristallog & Modelisat Mat Mineraux & Biol, UPRES A,CNRS 7036, F-54506 Vandoeuvre Les Nancy, France
[2] Univ Washington, Dept Geol Sci, Mineral Phys Grp, Seattle, WA 98195 USA
[3] Univ Durham, Dept Chem, Crystallog Grp, Durham DH1 3LE, England