Transformation of LiTi₂O₄ from Spinel to Ramsdellite on Heating

Time of flight powder neutron diffraction has been used to study the structural changes on heating LiTi2O4 from 25 to 1000 degrees C, A phase transition from the spinel to the ramsdellite form occurred between 875 and 925 degrees C; the two structure types coexisted, apparently in equilibrium over much of this range, About 300 degrees C below the transition, an anomalous change in the spinel structure was seen to occur, This anomaly was only observed in the parameters associated with Li and is thought to reflect migration of about 10% of the Li atoms from the 8a site, Above 925 degrees C, the ramsdellite form is stable and the structure was retained after rapid cooling, The structure of the high temperature ramsdellite form was refined by Rietveld analysis using the Pbnm space group, The refinement gave final R-wp and R-p values of 2.91 and 3.74%, respectively. (C) 1997 Academic Press.