Physics and Chemistry of Minerals

, Volume 32, Issue 7, pp 493–503

Neutron powder diffraction study of the orientational order–disorder phase transition in calcite, CaCO3

  • Martin T. Dove
  • Ian P. Swainson
  • Brian M. Powell
  • Donald C. Tennant
Original Paper

DOI: 10.1007/s00269-005-0026-1

Cite this article as:
Dove, M.T., Swainson, I.P., Powell, B.M. et al. Phys Chem Minerals (2005) 32: 493. doi:10.1007/s00269-005-0026-1

Abstract

Neutron powder diffraction studies of calcite on heating towards the orientational order–disorder phase transition show that the phase transition is not a simple analogue of an Ising-like transition, but more similar to a rotational analogue of Lindemann melting. The transition is precipitated by the librational amplitude of the carbonate molecular ions exceeding a critical value rather than a result of a statistical entropy of ‘wrong’ orientations. Using tested interatomic potentials the single-particle orientational potential and nearest-neighbour orientational interactions have been calculated.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Martin T. Dove
    • 1
    • 2
  • Ian P. Swainson
    • 2
  • Brian M. Powell
    • 2
  • Donald C. Tennant
    • 2
  1. 1.Department of Earth SciencesUniversity of CambridgeCambridgeUK
  2. 2.Canadian Neutron Beam Centre, National Research Council of CanadaChalk River LaboratoriesChalk RiverCanada