title: Structure determination of beta-Pb2ZnF6 by coupling multinuclear solid state NMR, powder XRD and ab initio calculations.
abstract: The results from one-dimensional multinuclear (19F, 207Pb and 67Zn) magic-angle spinning nuclear magnetic resonance experiments combined with the use of the ISODISPLACE program allow for the space group determination of beta-Pb2ZnF6 (no. 138 P4(2)/ncm). The structure was refined from X-ray powder diffraction data (a = 5.633 (1) A and c = 16.247 (1) A, Z = 4). beta-Pb2ZnF6 has one six-fold coordinated Zn, one eleven-fold coordinated Pb and five F non-equivalent crystallographic sites and is built from alternated layers parallel to the (a, b) plane; tilted ZnF4(2-) layers of corner sharing ZnF6(4-) octahedra and FPb+ layers of edge sharing FPb4(7+) tetrahedra. The structure of beta-Pb2ZnF6 was then optimized using the ab initio code WIEN2k and the calculated 67Zn EFG is in agreement with the NMR results. 19F-19F proximities and 19F-207Pb connectivities were evidenced using through-space and through-bond NMR correlation experiments, respectively, and support the proposed structure. 19F-207Pb J-coupling was also used to select fluorine resonances depending on the number of neighbouring lead ions, leading to an unambiguous assignment of the different 19F resonances.
authors.affiliation: Laboratoire des Oxydes et Fluorures, CNRS UMR 6010, Institut de Recherche en Ingénierie Moléculaire et Matériaux Fonctionnels, CNRS FR 2575, Université du Maine, Le Mans Cedex 9, France. charlotte.martineau.etu@univ-lemans.fr
authors.forename: Charlotte
authors.initials: C
authors.lastname: Martineau
authors.forename: Franck
authors.initials: F
authors.lastname: Fayon
authors.forename: Christophe
authors.initials: C
authors.lastname: Legein
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Buzaré
authors.forename: Monique
authors.initials: M
authors.lastname: Body
authors.forename: Dominique
authors.initials: D
authors.lastname: Massiot
authors.forename: François
authors.initials: F
authors.lastname: Goutenoire