@article{198494598184486eb76acd52ecd9eaa5,
title = "Experimental evidence of static disorder of carbonate ions in Ba-doped calcite",
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.",
keywords = "Amorphous calcium carbonate, Barium, Calcite, Static disorder",
author = "Shiho Marugata and Hiroyuki Kagi and Yuta Ijichi and Kazuki Komatsu and Xianyu Xue and Kazumasa Sugiyama",
note = "Funding Information: This work was supported by the JSPS Kakenhi [grant number JP18H05224, JP18K18780, JP18H05456].We are grateful to Dr. Makoto Tokuda for technical assistance with the XRD experiments at low temperature. XAFS analyses were performed at the BL12C beamline at the Photon Factory, KEK (proposal number: 2021G659). XRD measurements at low temperature was performed under the GIMRT Program of the Institute for Materials Research, Tohoku University. NMR measurements were undertaken under a joint research program carried out at the Institute for Planetary Materials, Okayama University, supported by “Joint Usage/Research Center” program by MEXT, Japan. This work was supported by the JSPS Kakenhi [grant number JP18H05224, 18K18780, JP18H05456]. Funding Information: This work was supported by the JSPS Kakenhi [grant number JP18H05224 , JP18K18780 , JP18H05456 ]. Funding Information: We are grateful to Dr. Makoto Tokuda for technical assistance with the XRD experiments at low temperature. XAFS analyses were performed at the BL12C beamline at the Photon Factory, KEK (proposal number: 2021G659). XRD measurements at low temperature was performed under the GIMRT Program of the Institute for Materials Research, Tohoku University. NMR measurements were undertaken under a joint research program carried out at the Institute for Planetary Materials, Okayama University , supported by “Joint Usage/Research Center” program by MEXT , Japan. This work was supported by the JSPS Kakenhi [grant number JP18H05224 , 18K18780 , JP18H05456 ]. Publisher Copyright: {\textcopyright} 2022 Elsevier Inc.",
year = "2022",
month = aug,
doi = "10.1016/j.jssc.2022.123258",
language = "English",
volume = "312",
journal = "Journal of Solid State Chemistry",
issn = "0022-4596",
publisher = "Academic Press Inc.",
}