Hg(3)AlF(6)O(2)H, a structure with a short interpolyhedral O...O distance.
The crystal structure of Hg(3)AlF(6)O(2)H, trimercury(II) aluminium hydrogen hexafluoride dioxide, can be derived from a slightly distorted cubic close-packed (ccp) arrangement of the metal atoms, where three quarters of the positions are occupied by Hg atoms and one quarter by Al atoms. The F and O atoms are considerably dislocated from the tetrahedral voids of this arrangement, thus forming [HgO(2)F(6)] polyhedra, with two short Hg-O distances, two intermediate Hg-F distances and four longer Hg-F distances, and nearly ideal [AlF(6)] octahedra. The H atoms are presumably located close to the inversion centre. Their positions were derived from crystal chemical arguments, and they take part in the formation of O-H.O hydrogen bonds between two O atoms, with an O.O distance of 2.562 (9) A.
Weil
Matthias
M
Institut für Mineralogie, Kristallographie und Strukturchemie, Technische Universität Wien, Getreidemarkt 9/171, A-1060 Vienna, Austria. mweil@mail.zserv.tuwien.ac.at