การหาโครงสร้างของโคบอลต์ทังสเตทโดยวิธีดิฟแฟรกชันของรังสีเอกซ์

Abstract

Cobalt tungstate, CoWo₄, crystallizes in the monoclinic system with cell dimensions a = 4.6378 ± 0.001, b = 5.684 ± 0.001, c = 4.949 ± 0.001 Å , β = 90.04 ± 0.03° , V = 131.61 Åᶾ, Dm = 7.75 ± 0.02 g.cm⁻3 at 28℃, Dₓ = 7.744 g.cm⁻3, space group P2/c and Ζ = 2 The structure has been determined by X-ray diffraction using Fourier and heavy atom methods. The difference synthesis was used to locate the oxygen atoms. Positional and isotropic thermal parameters were refined by the full matrix least squares method to a final R index of 0.09 for 225 independent observed re-flections. The structure of CoWo₄ is based on a distorted hexagonal close packing of oxygen atoms with cobalt and tungsten atoms each occupying one-fourth of the octahedral interstices. The similar octahedra of CoO₆ or WO₆ are joined by edges and the different octahedral by corners.