The description of Al, Si ordering in aluminosilicates using the cluster variation method

The cluster variation method (CVM) for determining the thermodynamics of bo th short-range and long-range order in this study was extended to complex a luminosilicate minerals. Using recently developed algorithms for the maximi zation of cluster entropies, it is possible to construct high-order cluster variation approximations for Ising lattices of complex topology. This stud y gives the essentials of developing CVM models for the Al, Si nets of neph eline, leucite, feldspar, and cordierite. The robustness of the method is d emonstrated by its ability to reproduce quantitatively recently published r esults of Monte Carlo simulations of Al, Si ordering in the Ising model wit h feldspar topology. The future prospects for the application of CVM to alu minosilicates are discussed.