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A computer-modelling study of CdCO3-CaCO3 solid solutions

Published online by Cambridge University Press:  05 July 2018

Q. Wang  and
N. H. de Leeuw
Q. Wang
Affiliation:
Department of Chemistry, University College London, London WC1H 0AJ, UK
N. H. de Leeuw*
Affiliation:
Department of Chemistry, University College London, London WC1H 0AJ, UK
*
*E-mail: [email protected]
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Abstract

We have applied atomistic simulation techniques to model the continuous CdCO3-CaCO3 solid solution and to investigate the thermodynamic properties. All inequivalent substitutional configurations were considered for the single unit cell and the (2x1x1) supercell for the full range of Cd concentrations, as well as doping between 0and 16.7 mol.% Cd for the (2x2x1) supercell. Our calculations show that segregation of Cd2+ and Ca2+ is energetically favourable when compared with any other cation distribution. No cation ordering is expected at high temperature and the system behaves as an ideal solid solution above 200 K, due to the configurational entropy. The lattice parameters change with the Cd concentration, where they are predicted to follow a linear relationship, due only to cation substitution but not cation ordering.

Keywords

calcitecadmiumsolid solutionthermodynamic properties
Type
Research Article
Information
Mineralogical Magazine , Volume 72 , Issue 1 , February 2008 , pp. 525 - 529
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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References

Davis, J.A., Fuller, C.C. and Cook, A.D. (1987) A model for trace element sorption processes at the calcite surface: Adsorption of Cd and subsequent solid-solution formation. Geochimica et Cosmochimica Ada, 51, 1477–1490.CrossRefGoogle Scholar
de Leeuw, N.H. and Parker, S.C. (2000) Modeling absorption and segregation of magnesium and cadmium ions to calcite surfaces: Introducing MgCO3 and CdCO3 potential models. Journal of Chemical Physics, 112, 4326–4333.CrossRefGoogle Scholar
Gale, J.D. and Rohl, A.L. (2003) The general utility lattice program. Molecular Simulation, 29, 291–341.CrossRefGoogle Scholar
Grau-crespo, R., Hamad, S., Catlow, C.R.A. and de Leeuw, N.H. (2007) Symmetry-adapted configurational modelling of fractional site occupancy in solids. Journal of Physics: Condensed Matter, 19, 256, 201–256, 217.Google Scholar
Pavese, A., Catti, M., Parker, S.C. and Wall, A. (1996) Modelling of the thermal dependence of structural and elastic properties of calcite, CaCO3 . Physics and Chemistry of Minerals, 23, 89–93.CrossRefGoogle Scholar
Reeder, RJ. (1996) Interaction of divalent cobalt, zinc, cadmium, and barium with the calcite surface during layer growth. Geochimica et Cosmochimica Ada. 60, 1543–1552.CrossRefGoogle Scholar
Stipp, S.L.S., Hochella, M.F., Parks, G.A. and Leckie, J.O. (1992) Cd2+ uptake by calcite, solid state diffusion, and the formation of solid-solution; Interface process observed with near surface sensitive techniques. Geochimica et Cosmochimica Ada, 56, 1941–1954.CrossRefGoogle Scholar
Tesoriero, AJ. and Pankow, J. F. (1995) Solid solution partitioning of Sr +, Ba + and Cd + to calcite. Geochimica et Cosmochimica Ada, 60, 1053–1063.Google Scholar