Crystal structure of moganite-type phosphorus oxynitride: relationship to other twinned-quartz-based structures.
The structure of moganite-type phosphorus oxynitride quenched from high-pressure high-temperature conditions has been refined using neutron powder diffraction data. This moganite-type structure, space group I2/a, Z = 12, is slightly less distorted with respect to the Imab aristotype than is moganite (a monoclinic form of silica). A close topological relationship has been identified between the moganite-type and orthorhombic BeH(2) structures indicating that SiO(2), PON and BeH(2) all adopt structures belonging to the twinned-quartz-based group. This group represents another possible structure type for systems composed of corner-sharing AX(4) tetrahedra. Structures of this group are obvious candidates for intermediate phases between the cristobalite and quartz types.
Laboratoire de Physicochimie des Matériaux, CNRS, 1 Place Aristide Briand, 92195 Meudon CEDEX, France. haines@cnrs-bellevue.fr
J
Haines
C
Chateau
JM
Léger
Le Sauze A
N
Diot
R
Marchand
S
Hull