BALANCE, UNIFORMITY, AND ASYMMETRY OF THE STRUCTURE OF VOLBORTHITE Cu3(OH)2(V2O7)⋅2H2O
A. A. Kashaev, I. V. Rozhdestvenskaya, I. I. Bannova, A. N. Sapozhnikov, O. D. Glebova
Keywords: volborthite structure, Cu-octahedra, V-tetrahedra, structure balance, structural homogeneity, hydrogen bond
Pages: 736-740
Abstract
Four structural models of volborthite Cu3(OH)2(V2O7)⋅2H2O (a = 10.646(2) Å, b = 5.867(1) Å, c =
14.432(2) Å, β = 95.19(1)°, V = 897.7(5) Å3, Z = 4, R/Rw = 0.038/0.046) calculated in the space groups determined from the systematic absences are compared. Based on the structure balance and the similarity of constituting polyhedra, values of the R factor, and isotropic thermal parameters, the space group Ia is found to be preferable, which is the only possible asymmetric and uniform variant. Hydrogen atoms of ОН-groups, oxygen atoms and, partially, hydrogen atoms of water are localized.
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