The crystal structure of fedotovite

The crystal structure of fedotovite, KzCu30(SO4)3 has been determined, space group C2/c, a 19.037(6), b 9.479(2), c 14.231(5) ~, (3 111.04(3) ~ Z = 8, Dx = 3.09 g/cm 3. 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 Cul and Cu2 atoms are distorted and flattened orthorhombic pyramids with Cu-O distances varying from 1.912 to 2.333/~,. the sixth neighbour of the both atoms is the copper atom lying at 2.975 and 2.981 ~ for Cu2 and Cul 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 A, a fifth at 2.558 A, and further sixth and seventh neighbours (oxygen and copper atoms) at 2.809 and 2.806 A, respectively.