ROBERT D. SHANNON, MUNIRPALLAM A. SUBRAMANIAN
Central Research Department, Experimental
Station 356/329, E.I. Du Pont de Nemours
Wilmington, Delaware 19880-0356, U.S.A.
ANTHONY N. MARIANO
48 Page Brook Road, Carlisle, Massachusetts 01741, U.S.A.
THURMAN E. GIER
P.O. Box 884, Chadds Ford, Pennsylvania 19317, U.S.A.
GEORGE R. ROSSMAN
Division of Geological and Planetary Sciences,
California Institute of Technology
Pasadena, California 91125, U.S.A.
The 1-MHz dielectric constants and loss factors of the minerals diaspore, euclase, ham bergite, sinhalite, danburite, datolite, beryllonite, and montebrasite and of the synthetic oxides La2Be2O5, A1P3O9, and NdP5O14 were determined. The dielectric polarizabilities of B2O3 and P2O5 derived from the dielectric constants of these compounds are 6.15 and 12.44 Å3, respectively. The dielectric constants of the above minerals and oxides, along with the dielectric polarizabilities of Li2O, Na2O, BeO, MgO, CaO, A12O3, Nd2O3, La2O3, SiO2, diaspore, and the derived values of the polarizabilities of B2O3 and P2O5, were used to calculate dielectric polarizabilities from the Clausius-Mosotti equation and to test the oxide additivity rule. The oxide additivity rule is valid to ± 0.5% for all except beryllonite. These compounds with deviations from additivity of 0.5-1.5%, along with previously studied aluminate and gallate gamets, chrysoberyl, spinel, phenacite, zircon, and olivine- type silicates, form a class of well-behaved oxides that can be used as a basis for compar ison of compounds that show larger deviations (>5%) caused by ionic or electronic conductivity, the presence of H2O or CO2, or structural peculiarities.
American Mineralogist, Volume 77, pages 10 1-106, 1992