Structural studies of a Li 2 O·4B 2 O 3 melt by high-temperature Raman spectroscopy and density functional theory

• Published in: CrystEngComm Vol. 19; no. 38; pp. 5721 - 5726
• Main Authors: Zheng, Guimei, Yao, Yanan, Zhang, Shujie, Wan, Songming, You, Jinglin
• Format: Journal Article
• Language: English
• Published: 2017
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/C7CE01131H

LiB 3 O 5 crystals are often grown from the Li 2 O·4B 2 O 3 high-temperature melt. Information about the melt structure is essential for interpreting the macro-properties of the melt and investigating the micro-process of LiB 3 O 5 crystal growth, but it still remains unknown. In this work, a method combining Raman spectroscopy and density functional theory (DFT) was employed to determine the Li 2 O·4B 2 O 3 melt structure. The results show that B 3 O 4 Ø 2 (Ø = bridging oxygen) and B 3 O 3 Ø 3 rings are the main species present in this melt. A small number of BØ 4 units and BO double bonds were also found in the Li 2 O·4B 2 O 3 melt. The BØ 4 units are formed via the connection of the non-bridging oxygen atoms in the B 3 O 4 Ø 2 rings to the boron atoms in the neighbouring B 3 O 3 Ø 3 rings; the BO bonds are formed by the breakage of the B 3 O 3 Ø 3 rings. The structure has been used to interpret the high viscosity and the viscosity anomaly phenomenon of the Li 2 O·4B 2 O 3 melt and to understand the micro-process of LiB 3 O 5 crystal growth.