Three New\nAlkaline Beryllium Borates LiBeBO₃, Li₆Be₃B₄O₁₂, and Li₈Be₅B₆O₁₈ in the Ternary Phase\nDiagrams Li₂O–BeO–B₂O₃

Abstract

The\nphase diagram in the Li₂O–BeO–B₂O₃ system has been systematically investigated\nby the methods of visual polythermal analysis, spontaneous crystallization,\nand X-ray diffraction. Three new alkaline beryllium borates, namely,\nLiBeBO₃, Li₆Be₃B₄O₁₂, and Li₈Be₅B₆O₁₈, were synthesized with molten fluxes based on Li₂O–B₂O₃ solvent in this system. All of the materials\nare centrosymmetric. The similarity of the fundamental building block\nof the title compounds has been compared. Thermal analysis and powder\nXRD studies were applied to determine phase relation and their incongruent\nmelting behavior. The UV–vis diffuse reflectance spectroscopy\ndemonstrated that the UV cutoff edges of the aforementioned materials\nare all below 200 nm.