High Pressure Synthesis, Crystal Growth and Magnetic Properties of TiOF

Abstract Polycrystalline samples of TiOF have been prepared at 1300 °C and 8 GPa, with small single crystals grown at the same conditions. The crystal structure remains tetragonal rutile-type down to at least 90 K (space group P4 2 / mnm , a = 4.6533 (2) A and c = 3.0143 (2) A at 90 K) and the Ti(O,F) 6 octahedra are slightly compressed, consistent with Jahn-Teller distortion of 3d 1 Ti 3+ . Diffuse scattering reveals disordered structural correlations that may arise from local cis -order of oxide anions driven by covalency. TiOF is paramagnetic down to 5 K and observation of a small paramagnetic moment and a substantial Pauli term indicates that the d-electrons are partially delocalised.