Estimation of the lattice entropy of rare-earth compounds

Resolution of excess entropy of many types of transitions and estimation of standard entropy at 298.15K of compounds, for which experimental entropies have not yet been measured, depend on a reliable estimation of the lattice entropy. By taking into account the effects of cation mass and molar volume of the rare-earth compounds, the following formula is proposed for the estimation of the lattice entropy of isostructural iso-anionic rare-earth compounds. We have investigated 32 compounds, and found good agreements between estimated and experimental entropies.