Neutron Diffraction Refinement of CaWO4

The CaWO4 structure has been refined, starting with the parameters of Sillén and Nylander, using two zones of neutron diffraction data. The oxygen coordinates with the origin of the cell at the W atom (4̄) are x=0.2413 (σ=0.0005), y=0.1511 (σ=0.0006), z=0.0861 (σ=0.0001). The slightly distorted WO4 tetrahedron contains a W–O distance of 1.788 Å (σ=0.003) and angles of 113° 27′ (σ=14′) and 107° 56′ (σ=0.09′). Close nonbonded approaches are Ca–O=2.48 Å and O–O=2.77 Å. Anisotropic thermal vibration parameters were also determined.