Ge(0.57)Ti(0.43)O(2): a new high-pressure material with rutile-type crystal structure

Single crystals of a GeO(2)–TiO(2) solid solution with the corresponding composition Ge(0.57)Ti(0.43)O(2) (germanium titanium tetra­oxide) were obtained by devitrification of germania-titania glass at high pressure and temperature. The new compound crystallizes in the rutile structure type (space group P4(2)/mnm), where Ge and Ti share the same position M (site symmetry m.mm), with occupancy values of 0.57 (3) and 0.43 (3), respectively, and one O-atom position (m.2m). The M site is in a sixfold O-atom coordination and, as in the original TiO(2) rutile structure, an elongation of the O—M—O bonds along the c-axis direction of the coordination polyhedron and deviation of the angles from 90° lead to a decrease in the coordination symmetry from octa­hedral to tetra­gonal. The Ge and Ti atoms are fully disordered in the structure, which indicates that the rutile structure is surprisingly pliant given the differing sizes of the two cations.