Thermochemical study of vaporization of Li4TiO4 by a mass spectrometric Knudsen effusion method

The vaporization of Li4TiO4 has been studied by a mass spectrometric Knudsen effusion method in the temperature range 1082-1582 K. Identified vapors are Li(g), LiO(g), Li2O(g) and Li3O(g). When the vaporization proceeds, the content of Li2O in the Li4TiO4 sample decreases and the condensed phase of the sample changes to β-Li4TiO4 plus 1-Li2TiO3 below 1323 K, to β-Li4TiO4 plus h-Li2TiO3 in the range 1323-1473 K and to h-Li2TiO3 plus liquid above 1473 K. On the basis of the partial pressure data, the enthalpies of formation for β-Li4TiO4 from elements and from constituent oxides have been determined to be ΔHof,298(β-Li4TiO4, s) = -2247.8±14.3 kJ mol-1 and ΔHofox,298(β-Li4TiO4, s) = -107.3±14.3 kJ mol-1, respectively. (orig.)