The Crystal Structure of Fedotovite, K2Cu3O(SO4)3

G. L. Starova, S. K. Filatov, V. S. Fundamensky and L. P. Vergasova
Department of Crystallography, Leningrad State University, Univers. Emb. 7/9, Leningrad 199164, USSR
INPO ‘Burevestnik’, Leningrad
Institute of Volcanology, the Academy of Sciences of the USSR, Petropavlovsk-Kamchatsky, USSR

Abstract: The crystal structure of fedotovite, K2Cu3O(SO4)3 has been determined, space group C2/c, a 19.037(6), b 9.479(2), c 14.231(5) Å, β 111.04(3)°, Z = 8, Dx = 3.09 g/cm3. The main units of the fedotovite structure are formed around two additional oxygen atoms and consist of edge-sharing [OCu4] tetrahedra and four [SO4] tetrahedra attached to them. The units are further connected by two [SO4] tetrahedra, building distinct layers parallel to the yz plane. These layers are interconnected by potassium atoms. In the fedotovite structure, the three kinds of copper atoms are fivefold (4 + 1) coordinated to oxygen atoms with a strong Jahn-Teller effect. The coordination polyhedra of Cu1 and Cu2 atoms are distorted and flattened orthorhombic pyramids with Cu-O distances varying from 1.912 to 2.333 Å, the sixth neighbour of the both atoms is the copper atom lying at 2.975 and 2.981 Å for Cu2 and Cu1 respectively. The coordination environment of the Cu3 atom is a distorted elongated orthorhombic pyramid with four Cu-O distances from 1.943 to 1.961 Å, a fifth at 2.558 Å, and further sixth and seventh neighbours (oxygen and copper atoms) at 2.809 and 2.806 Å, respectively.

Keywords: fedotovite • crystal structure

Mineralogical Magazine; December 1991 v. 55; no. 381; p. 613-616; DOI: 10.1180/minmag.1991.055.381.14
© 1991, The Mineralogical Society
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