Crystal structure of new polymorphic modification β-Ca3B2SiO8, β-α phase transition and thermal expansion of α- and β-modifications
- Authors: Bubnova R.S.1,2, Volkov S.N.1, Yukhno V.A.1, Krzhizhanovskaya M.G.2
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Affiliations:
- Grebenshchikov Institute of Silicate Chemistry
- St. Petersburg State University
- Issue: Vol 42, No 4 (2016)
- Pages: 349-358
- Section: Article
- URL: https://journals.rcsi.science/1087-6596/article/view/215615
- DOI: https://doi.org/10.1134/S1087659616040052
- ID: 215615
Cite item
Abstract
Single crystals of the β-Ca3B2SiO8 new monoclinic modification have been obtained by cooling the melt of a stoichiometric composition. The crystal structure has been determined from the single crystal X-ray diffraction data and refined with R = 0.059 (wR = 0.069) in the monoclinic space group P21/m. The thermal behavior of the synthetic borosilicate has been studied. At 472 ± 5°С, a reversible phase transition of the first order occurs, leading to the formation of the orthorhombic α-Ca3B2SiO8 modification. The thermal expansion of α- and β-modifications of Ca3B2SiO8 is anisotropic: (α11 = 15, α22 = 16, α33 =–1, αV = 30 × 10–6°С–1) and α11 = 9, α22 = 28, α33 = 1, αV = 38 × 10–6°C–1, respectively.
About the authors
R. S. Bubnova
Grebenshchikov Institute of Silicate Chemistry; St. Petersburg State University
Email: s.n.volkov@inbox.ru
Russian Federation, nab. Makarova 2, St. Petersburg, 199034; Universtitetskaya nab. 7/9, St. Petersburg, 199034
S. N. Volkov
Grebenshchikov Institute of Silicate Chemistry
Author for correspondence.
Email: s.n.volkov@inbox.ru
Russian Federation, nab. Makarova 2, St. Petersburg, 199034
V. A. Yukhno
Grebenshchikov Institute of Silicate Chemistry
Email: s.n.volkov@inbox.ru
Russian Federation, nab. Makarova 2, St. Petersburg, 199034
M. G. Krzhizhanovskaya
St. Petersburg State University
Email: s.n.volkov@inbox.ru
Russian Federation, Universtitetskaya nab. 7/9, St. Petersburg, 199034