Abstract
Excess Gibbs free energy surfaces generated at various pressure and temperature conditions for the C2/c pyroxene quadrilateral compositional space Mg2Si2O6−CaMgSi2O6−CaFeSi2O6−Fe2Si2O6 with a two-body static interionic potential summation (Ottonello et al. 1992) have been fitted to 4 component extensions of the Wohl and Kohler macroscopic interactions models. The mean precision (272j/mol) and the maximum observed bias (1.19 Kj/mol) are roughly similar for the two macroscopic formulations, but Wohl's extension is preferred due to its relative simplicity.
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Ottonello, G. Interactions and mixing properties in the (C2/c) clinopyroxene quadrilateral. Contrib Mineral Petrol 111, 53–60 (1992). https://doi.org/10.1007/BF00296577
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DOI: https://doi.org/10.1007/BF00296577