title: The 136-atom structure of ZrP2O7 and HfP2O7 from powder diffraction data.
abstract: There has been considerable debate in the literature about the true room-temperature structure of ZrP2O7 and related materials. In this article we describe how a combination of information from solid-state 31P NMR and powder diffraction data can be used to determine the structure of this 136 unique-atom material. The structure has been solved using a combination of simulated annealing and Rietveld refinement performed simultaneously on X-ray and neutron diffraction data. Despite the close to cubic metric symmetry of the material, we show how its true orthorhombic structure (space group Pbca) can be refined to a high degree of precision.
authors.affiliation: Department of Chemistry, Science Laboratories, University of Durham, South Road, Durham, DH1 3LE, UK.
authors.forename: Graham W
authors.initials: GW
authors.lastname: Stinton
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hampson
authors.forename: John S O
authors.initials: JS
authors.lastname: Evans