title: The room-temperature superstructure of ZrP2O7 is orthorhombic: there are no unusual 180 degrees P-O-P bond angles.
abstract: The structure of room-temperature ZrP2O7 is shown to be orthorhombic by a combination of high-resolution synchrotron powder diffraction and single-crystal synchrotron diffraction data. Small nontwinned single crystals were obtained by synthesizing the compound using solvothermal methods at temperatures below the cubic to orthorhombic phase transition. The average P-O-P angle is 146 degrees. DFT calculations (B3LYP/AUG-cc-pVDZ) on the isolated P2O7(4-) anion yield a P-O-P angle of 153.42 degrees and indicate that the barrier to inversion is of the order 3.6 kJ mol(-1).
authors.affiliation: Laboratory of Crystallography, Ecole Polytechnique Fédérale de Lausanne, BSP Dorigny, CH-1015 Lausanne, Switzerland. hbirkedal@chem.au.dk
authors.forename: Henrik
authors.initials: H
authors.lastname: Birkedal
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Krogh Andersen
authors.forename: Alla
authors.initials: A
authors.lastname: Arakcheeva
authors.forename: Gervais
authors.initials: G
authors.lastname: Chapuis
authors.forename: Poul
authors.initials: P
authors.lastname: Norby
authors.forename: Philip
authors.initials: P
authors.lastname: Pattison