Experimental Evidence of Static Disorder of Carbonate Ions in Ba-Doped Calcite

42 Pages Posted: 29 Mar 2022

See all articles by Shiho Marugata

Shiho Marugata

affiliation not provided to SSRN

Hiroyuki Kagi

University of Tokyo

Yuta Ijichi

affiliation not provided to SSRN

Kazuki Komatsu

affiliation not provided to SSRN

Xianyu Xue

affiliation not provided to SSRN

Kazumasa Sugiyama

affiliation not provided to SSRN

Abstract

Incorporation of structurally incompatible Ba2+ into calcite by crystallization via amorphous calcium carbonate induces the extinction of 113 reflection in the X-ray diffraction patterns even at room temperature. It has recently been hypothesized that this phenomenon is caused by the static disorder of CO32– in Ba-doped calcite exhibiting notable increase in the unit-cell volume. To experimentally clarify this hypothesis, we investigated the behavior of CO32– and the local structure in Ba-doped calcite samples. Powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements indicated that CO32– ions in Ba-doped calcite were disordered even at low temperatures down to 91K. 13C MAS NMR spectra suggest that Ba atoms in calcite are randomly substituted for Ca atoms. The Ca K-edge XAFS and the IR absorption spectra indicated the symmetry reduction of CO32– with increasing Ba content. These changes in the local structure by incorporating incompatible Ba2+ into calcite cause the static disorder of CO32– at room temperature.

Keywords: static disorder, calcite, barium, amorphous calcium carbonate

Suggested Citation

Marugata, Shiho and Kagi, Hiroyuki and Ijichi, Yuta and Komatsu, Kazuki and Xue, Xianyu and Sugiyama, Kazumasa, Experimental Evidence of Static Disorder of Carbonate Ions in Ba-Doped Calcite. Available at SSRN: https://ssrn.com/abstract=4069249 or http://dx.doi.org/10.2139/ssrn.4069249

Shiho Marugata

affiliation not provided to SSRN ( email )

No Address Available

Hiroyuki Kagi (Contact Author)

University of Tokyo ( email )

Yuta Ijichi

affiliation not provided to SSRN ( email )

No Address Available

Kazuki Komatsu

affiliation not provided to SSRN ( email )

No Address Available

Xianyu Xue

affiliation not provided to SSRN ( email )

No Address Available

Kazumasa Sugiyama

affiliation not provided to SSRN ( email )

No Address Available

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