Oxide Ion Disorder in Nd2Hf2O7: Oxide Ion Disorder in Nd2Hf2O7

The compound Nd2Hf2O7 was synthesized via a solid-state route and the crystal structure determined by electron diffraction and Rietveld refinement of both X-ray and neutron diffraction data. A small amount of disorder was found on the anion sublattice, while no evidence of disorder in the cation sublattice could be verified. The compound is cubic with space group Fd (3) over barm, structurally lying between the ideal pyrochlore and fluorite forms, with 0.26% of the oxide ions residing on the 8a sites usually vacant in pyrochlores. The lattice constant is 10.6469(2) angstrom, and the overall fit parameter was R-wp=0.0398.