Distortions of the calcite and aragonite atomic structures from interstitial water

S. Sinha, Peter Rez

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Amorphous calcium carbonate (ACC), as observed by diffraction or infra-red spectroscopy, is especially significant as a precursor in biomineralization. The atomic structure and mechanisms for transformation to the crystalline phases are still unknown. It is conceivable that insertion of water molecules could give rise to distortions that result in the observed diffraction patterns and infrared spectra. We use the VASP density functional theory code to relax model supercells with 24 formula units of CaCO3 where we have inserted up to 5 water molecules, corresponding to 3.75 wt%. The main effect is tilting of the carbonate planes, which can be as high as 50°. This leads to a range of Ca-O distances that are consistent with the observed changes in the IR spectra in ACC. The spread in cation-cation distances is not enough to destroy coherent diffraction from regions 70 nm across, and so does not explain amorphous diffraction profiles.

Original languageEnglish (US)
Pages (from-to)56-62
Number of pages7
JournalMaterials Chemistry and Physics
Volume157
DOIs
StatePublished - May 1 2015

Fingerprint

aragonite
Calcium Carbonate
Calcite
calcite
atomic structure
interstitials
Diffraction
calcium carbonates
Calcium carbonate
Cations
Water
Positive ions
diffraction
water
Biomineralization
Crystal atomic structure
cations
Molecules
Carbonates
Diffraction patterns

Keywords

  • Ab-initio calculations
  • Biomaterials
  • Computer modeling and simulations
  • IR

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

Distortions of the calcite and aragonite atomic structures from interstitial water. / Sinha, S.; Rez, Peter.

In: Materials Chemistry and Physics, Vol. 157, 01.05.2015, p. 56-62.

Research output: Contribution to journalArticle

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