Publication
Reference
Spahr Dominik, Bayarjargal Lkhamsuren, Vinograd Victor, Luchitskaia Rita, Milman Victor, Winkler Björn (2019). A new BaCa(CO3)2 polymorph. Acta. Crystallogr. B., 75, 291 - 300.
Names
  • Dominik Spahr
  • Lkhamsuren Bayarjargal
  • Victor Vinograd
  • Rita Luchitskaia
  • Victor Milman
  • Björn Winkler
Article and keywords
Title
A new BaCa(CO3)2 polymorph
Abstract
A new polymorph of the double carbonate BaCa(CO3)2, `a C2 phase', has been synthesized. Its structure has been obtained by density- functional-theory-based (DFT-based) model calculations and has been refined by Rietveld analysis of X-ray powder diffraction data. The structure of the new polymorph differs significantly from those of the established polymorphs barytocalcite, paralstonite and alstonite. The unit-cell parameters of the new monoclinic (space group C2) compound are a = 6.6775 (5), b = 5.0982 (4), c= 4.1924 (3) \rA, β = 109.259° (1). The new compound has been further characterized using Raman spectroscopy. This work shows that earlier studies have misidentified the products of an established synthesis route and that findings based on the incorrect identification of the synthesis product concerning the suitability of barytocalcite as a matrix for the retention of radioactive isotopes will need to be reconsidered.
Keywords
Raman spectra, mid-IR, far-IR, X-ray diffraction, data analysis, vibration theory, band position, band mode assignement, high temperature, phase change, mineral, carbonate, barytocalcite, paralstonite, calcite, witherite, BaCa(CO3)3
Content
spectral data, band list data, experimental physics
Year
2019
Journal
Acta Crystallographica Section B
Volume
75
Number
3
Pages
291 - 300
Document type
article
Publication state
published
Doi
10.1107/S2052520619003238
Identifiers