Reinvestigation on the phase transition of a LiB sub(3)O sub(5) crystal near its melting point

• Published in: Journal of crystal growth Vol. 435; pp. 1 - 5
• Main Authors: Wan, S M, Zheng, G M, Feng, D X, Yao, Y N, Zhao, Y, You, J L, Hu, Z G
• Format: Journal Article
• Language: English
• Published: 01.02.2016
• Subjects: Crystal growth; Crystals; LBO; Lithium tetraborate; Mathematical models; Melting points; Phase diagrams; Phase transformations
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2015.11.010

Raman spectroscopy has been applied to investigate in-situ the phase transition of a LBO (LiB sub(3)O sub(5)) crystal near its melting point in order to explain the discrepancies between the experimental results observed in the LBO crystal growth process and the predicted results obtained from the Li sub(2)O-B sub(2)O sub(3) phase diagram. When the LBO crystal begins to melt, it first decomposes to the kinetic products Li sub(2)B sub(4)O sub(7) and B sub(2)O sub(3); then the Li sub(2)B sub(4)O sub(7) reacts with the undecomposed LBO to form the thermodynamic product Li sub(3)B sub(7)O sub(12). On the basis of these results, a set of models have been proposed to describe the structural transformations present in the phase transition. Additionally, our experimental result indicates that Li sub(3)B sub(7)O sub(12) is stable/metastable at room temperature. Its Raman spectrum has been calculated by the density functional theory method for identification of the Li sub(3)B sub(7)O sub(12) crystalline phase in a mixture. The result shows that Li sub(3)B sub(7)O sub(12) has three strong characteristic Raman peaks located around 595, 775 and 1040 cm super(-1).