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 ($\text{4̄}$ ) 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.