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Please use this identifier to cite or link to this item: http://hdl.handle.net/1834/4103

Title: Thermochemistry of strontium incorporation in aragonite from atomistic simulations
Authors: Grau-Crespo, R.
Ruiz-Hernández, S. E.
Ruiz-Salvador, A. R.
De Leeuw, N. H.
ASFA Terms: Aragonite
Coral reefs
Thermodynamic activity
Strontium
Issue Date: 2010
Publisher: Elsevier
Citation: Geochimica et Cosmochimica Acta, 74(2010). p. 1320-1328
Abstract: We have investigated the thermodynamics of mixing between aragonite (orthorhombic CaCO3) and strontianite (SrCO3). In agreement with experiment, our simulations predict that there is a miscibility gap between the two solids at ambient conditions. All SrxCa1 xCO3 solids with compositions 0.12 < x < 0.87 are metastable with respect to separation into a Ca-rich and a Sr-rich phase. The concentration of Sr in coral aragonites (x 0.01) lies in the miscibility region of the phase diagram, and therefore formation of separated Sr-rich phases in coral aragonites is not thermodynamically favorable. The miscibility gap disappears at around 380 K. The enthalpy of mixing, which is positive and nearly symmetric with respect to x = 0.5, is the dominant contribution to the excess free energy, while the vibrational and configurational entropic contributions are small and of opposite sign. We provide a detailed comparison of our simulation results with available experimental data. Se investigó la actividad termodinámica existente entre la mezcla de la aragonita y el estroncio. Se ofrecen todos los datos experimentales y los resultados de la simulación efectuada predicen que hay un vacío en condiciones de ambiente.
URI: http://hdl.handle.net/1834/4103
Related document: doi:10.1016/j.gca.2009.10.049
ISSN: 0016-7037
Appears in Collections:1. Artículos científicos

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