In situ high-temperature X-ray diffraction study of the Rb2O-B2O3 glass forming system by R. S. Bubnova, M. G. Krzhizhanovskaya, I. G. Polyakova, and S. K. Filatov

Crystal Research and Technology

Cryst. Res. Technol. 40, 73 (2005) - Abstract -

In situ high-temperature X-ray diffraction study of the Rb₂O-B₂O₃ glass forming system

R. S. Bubnova, M. G. Krzhizhanovskaya*, I. G. Polyakova, and S. K. Filatov*

Institute of the Silicate Chemistry of the Russian Academy of Sciences. Ul. Odoevskogo, 24/2, 199155, St. Petersburg, Russia
*Department of Crystallography, St. Petersburg State University, University Emb. 7/9, 199034, St. Petersburg, Russia

Keywords	phase diagram, melting processes, rubidium borates, glass forming materials
PACS	61.10.Nz, 61.66.Fn, 64.70.Dv, 64.70.Kb
DOI	10.1002/crat.200410309

The results of X-ray structural analysis, in situ powder high temperature X-ray diffraction (HTXRD), DTA and annealing studies are summarized to refine the phase equilibria in the Rb₂O-B₂O₃ system in air. Samples were prepared by solid state reaction as well as by the crystallisation of glasses. Investigations show that, in the latter case, high-temperature metastable phases crystallise first, and it takes some months to reach phase equilibria. The recent determination of crystal structures of Rb₂B₄O₇, Rb₃B₇O₁₂, Rb₅B₁₉O₃₁, α,β-RbB₃O₅ and β-RbB₅O₈ along with the HTXRD and DTA study led to substantial revising of the Rb₂O-B₂O₃ phase diagram between the 5-50 mol. % Rb₂O compositions. New compounds Rb₃B₂O₁₂ and Rb₅B₁₉O₃₁ and new phase relations in this connection are presented. The low (α) and high temperature (β) modifications of RbB₃O₅ were discovered and α<->β transition is studied in details by powder HTXRD.

The full text of this paper in pdf-Format:

If you have come directly to this page, click this symbol

to go to the CRT homepage.