The room-temperature superstructure of ZrP2O7 is orthorhombic: There are no unusual 180 degrees P-O-P bond angles
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 P2O74- 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).
Keywords: negative thermal-expansion
Author Address: Birkedal, H Aarhus Univ, Dept Chem, Langelandsgade 140, DK-8000 Aarhus C, Denmark Ecole Polytech Fed Lausanne, BSP Dorigny, Crystallog Lab, CH-1015 Lausanne, Switzerland Univ Stockholm, Arrhenius Lab, Dept Struct Chem, S-10691 Stockholm, Sweden RAS, Baykov Inst Met & Mat, Moscow 119991, Russia Univ Oslo, Dept Chem, N-0315 Oslo, Norway European Synchrotron Radiat Facil, Swiss Norwegian Beam Lines, F-38043 Grenoble, France
Record created on 2006-07-07, modified on 2016-08-08