Electroneutrality effects on aluminum order in sodium feldspar: A twohyphen;dimensional model

摘要

A twohyphen;dimensional analog model for the mineral albite is investigated in order to evaluate the effect of local charge neutrality on the aluminumndash;silicon orderndash;disorder in the crystal. The configurational entropy and order parameter, as functions of the temperature, are calculated within the quasichemical approximation. Model calculations using our definition of local charge balance show a significant change in the temperature dependence of the entropy and order parameter over what would be expected if local charge balance were not rigorously obeyed.