Thermodynamic properties of geikielite (MgTiO3) and ilmenite (FeTiO3) derived from vibrational methods combined with Raman and infrared spectroscopic data

We present a model for the lattice vibrational density of states MgTiO3 (geikielite) and FeTiO3 (ilmenite) that predicts thermodynamic properties, in agreement with observational data. The is based on Kieffer’s method combined spectroscopic For both substances experimental data sets are influenced by non-stoichiometry. geikielite affects volume, whereas ilmenite volume bulk modulus affected. show enables predicting moduli pressure–temperature space. demonstrate intrinsic anharmonicity or electronic effects significantly affect heat capacity ilmenite, not case geikielite. use to derive multiple-Einstein models, from which we properties insignificantly dispersion Grüneisen, mode-q parameters substances. our results enable shear solid solution formed ilmenite. Geikielite added database system MgO–SiO2–FeO, modeling phase stability physical titanium-rich reservoirs Earth’s Moon.