New process of preparation, X-ray characterisation, structure and vibrational studies of a solid solution LiTiOAs1−xPxO4 (0⩽x⩽1)

LiTiOAs1−xPxO4 (0⩽x⩽1) compounds have been prepared using solutions of Li, Ti, As and P elements as starting products. Selected compositions have been investigated by powder X-ray or neutrons diffraction analysis, Raman and infrared spectroscopy. The structure of LiTiOAs1−xPxO4 (x=0, 0.5 and 1) samples determined by Rietveld analysis is orthorhombic with Pnma space group. It is formed by a 3D network of TiO6 octahedra and XO4 (X=As1−xPx) tetrahedra where octahedral cavities are occupied by lithium atoms. TiO6 octahedra are linked together by corners and form infinite chains along a-axis. Ti atoms are displaced from the centre of octahedral units in alternating short (1.700–1.709 Å) and long (2.301–2.275 Å) Ti–O bonds. Raman and infrared studies confirm the existence of Ti–O–Ti chains. Thermal stability of LiTiOAsO4 has been reported.