Coordination polyhedra TiOn in crystal structures

The Voronoi-Dirichlet polyhedra (VDP) and the method of intersecting sphere s were used to perform crystal-chemical analysis of 532 compounds containin g 940 crystallographic sorts of titanium atoms in TiOn coordination polyhed ra. It was found that Ti(IV) or Ti(III) atoms can coordinate four to eight oxygen atoms. For a constant valence state and a constant coordination numb er (C.N.) of titanium, the Ti-O bond lengths vary by 0.1-1.0 Angstrom. At C .N. > 5, the volume of the metal VDP remains virtually unchanged; when the C.N. decreases to 4, the VDP volume increases by 2-3 Angstrom (3). For a co nstant C.N., Ti(IV) -->Ti(III) transition is accompanied by an increase in the VDP volume of metal atoms of 0.5-1.9 Angstrom (3). The VDP characterist ics of the Ti atoms can be used to determine their valence state and to ide ntify the titanium-metal bonds in the structures of compounds.