Experimental evidence of static disorder of carbonate ions in Ba-doped calcite

Shiho Marugata, Hiroyuki Kagi, Yuta Ijichi, Kazuki Komatsu, Xianyu Xue, Kazumasa Sugiyama

Research output: Contribution to journalArticlepeer-review

Abstract

Incorporation of structurally incompatible Ba2+ into calcite by crystallization via amorphous calcium carbonate induces extinction of 113 reflection in X-ray diffraction patterns even at room temperature. Recently, this phenomenon has been hypothesized as deriving from the static disorder of CO32− in Ba-doped calcite, creating a marked increase in the unit-cell volume. To clarify this hypothesis by experiments, behaviors of CO32− and local structures in Ba-doped calcite samples were investigated. Powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) indicate that CO32− ions in Ba-doped calcite are disordered, even at 91K. 13C MAS NMR spectra suggest that Ba atoms in calcite are substituted randomly for Ca atoms. The Ca K-edge X-ray absorption fine structure (XAFS) and the IR absorption spectra indicated reduction of CO32− symmetry with increasing Ba content. These local structure changes by incorporation of incompatible Ba2+ into calcite cause static disorder of CO32− at room temperature.

Original languageEnglish
Article number123258
JournalJournal of Solid State Chemistry
Volume312
DOIs
Publication statusPublished - Aug 2022

Keywords

  • Amorphous calcium carbonate
  • Barium
  • Calcite
  • Static disorder

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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