An anisotropic equation of state for solid solutions, with application to plagioclase

Abstract

Summary This paper presents a framework for building anisotropic equations of state for solid solutions. The framework satisfies the connections between elastic and thermodynamic properties required by Maxwell’s relations. It builds on a recent anisotropic equation of state for pure phases under small deviatoric stresses, adding a dependence on a vector n, whose components ni contain the molar amounts of independent endmembers in the solid solution. These endmembers may have distinct chemical compositions, site species occupancies or electronic spin states. The high albite-anorthite (C$\bar{\text{1}}$) plagioclase solid solution is used to illustrate the formulation.