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First Principles Based Calculations of the CaCO3 - MgCO3 and CdCO3-MgCO3 Subsolidus Phase Diagrams



Benjamin P. Burton, A Van de Walle


Planewave pseudopotential calculations of formation energies for several ordered supercells were used as bases for first principles calculations of the CaCO3 - MgCO3 and CdCO3 - MgCO3 phase diagrams. Calculated phase diagrams are in qualitative to semiquantitative agreement with experiment, with the exception that two unobserved phases Ca3Mg(CO3)4 and CdMg3(CO3)4 are predicted. No new phases are predicted in the CaCO3 - MgCO3 system, but a low lying metastable Ca3Mg(CO3)4 state, analogous to the CdMg3(CO3)4 phase is predicted. All of the predicted lowest lying metastable states have dolomite related structures; i.e. they are layer structures in which AmBn cation layers lie perpendicular to the rhombohedral [111] vector.
Physics and Chemistry of Minerals
30 No. 2


CaCO<sub>3</sub>, carbonates, CdCO<sub>3</sub>, first principles, mustastable phase equilibria, phase diagram calculation


Burton, B. and Van, A. (2003), First Principles Based Calculations of the CaCO<sub>3</sub> - MgCO<sub>3</sub> and CdCO<sub>3</sub>-MgCO<sub>3</sub> Subsolidus Phase Diagrams, Physics and Chemistry of Minerals, [online], (Accessed April 13, 2024)
Created March 1, 2003, Updated February 19, 2017