Dielectric constants of silicate garnets and the oxide additivity rule

A study was conducted to determine the dielectric constants of silicate garnets and analyze the oxide additivity rule. Additivity, normal bond distance and bond valence deviations were observed and were attributed to garnet structural constraints caused by edge sharing. Pyrope garnets showed high polarizability and magnesium thermal vibration ellipsoids and excess entropy while grossular garnets exhibited low dielectric polarizability. Spessartine and andradite garnets showed additivity deviations proportional to the intermediate values of bond valences.