Excess enthalpy of mixing of mineral solid solutions derived from density-functional calculations.

ABSTRACT: Calculations using the density-functional theory (DFT) in combination with the single defect method were carried out to determine the heat of mixing behaviour of mineral solid solution phases. The accuracy of this method was tested on the halite-sylvite (NaCl-KCl) binary, pyrope-grossular garnets (Mg3Al2Si3O12-Ca3Al2Si3O12), MgO-CaO (halite structure) binary, and on Al/Si ordered alkali feldspars (NaAlSi3O8-KAlSi3O8); as members for coupled substitutions, the diopside-jadeite pyroxenes (CaMgSi2O6-NaAlSi2O6) and diopside-CaTs pyroxenes (CaMgSi2O6-CaAlAlSiO6) were chosen for testing and, as an application, the heat of mixing of the tremolite-glaucophane amphiboles (Ca2Mg5Si8O22(OH)2-Na2Mg3Al2Si8O22(OH)2) was computed. Six of these binaries were selected because of their experimentally well-k

SUBMITTER: Benisek A 

PROVIDER: S-EPMC7024695 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature