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Physics and Chemistry of Minerals

, Volume 34, Issue 8, pp 573–580 | Cite as

BaCO3: high-temperature crystal structures and the PmcnR3m phase transition at 811°C

  • Sytle M. AntaoEmail author
  • Ishmael Hassan
Original Paper

Abstract

The temperature (T) evolution of the barium carbonate (BaCO3) structure was studied using Rietveld structure refinements based on synchrotron X-ray diffraction and a powdered synthetic sample. BaCO3 transforms from an orthorhombic, Pmcn, α phase to a trigonal, R3m, β phase at 811°C. The orthorhombic BaCO3 structure is isotypic with aragonite, CaCO3. In trigonal R3m BaCO3, the CO3 group occupies one orientation and shows no rotational disorder. The average <Ba–O> distances increase while the <C–O> distances decrease linearly with T in the orthorhombic phase. After the 811°C phase transition, the <Ba–O> distances increase while C–O distances decrease. There is also a significant volume change of 2.8% at the phase transition.

Keywords

Barium carbonate BaCO3 Witherite High-temperature structures Phase transition Rietveld refinements Synchrotron radiation 

Notes

Acknowledgments

This research was carried out in part at the National Synchrotron Light Source, Brookhaven National Laboratory (BNL), which is supported by the U.S. Department of Energy, Division of Materials Sciences and Division of Chemical Sciences, under Contract No. DE-AC02-98CH10886. We thank J. C. Hanson for his help in performing the synchrotron experiments.

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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Advanced Photon SourceArgonne National LaboratoryArgonneUSA
  2. 2.Department of ChemistryUniversity of the West IndiesKingston 7Jamaica

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