The first systematic study of the BaO–B₂O₃ system and barium orthoborate Ba₃B₂O₆ (3BaO·B₂O₃) was reported in 1949. Thereafter, the system was repeatedly refined but the structure of Ba₃B₂O₆ compound has not been adequately studied yet. In our study we have, for the first time, obtained the crystalline samples of Ba₃B₂O₆. The solved structure (Pbam, a = 13.5923(4) Å, b = 13.6702(4) Å, c = 14.8894(3) Å) belongs to the class of ‘anti-zeolite’ borates with a pseudotetragonal [Ba₁₂(BO₃)₆]⁶⁺ cation pattern which contains channels along the c axis filled with anionic clusters. The Ba₃B₂O₆ compound may be regarded as a fluorine-free end-member of the Ba₃(BO₃)_2–xF_3x solid solution. The BaO–B₂O₃ phase diagram presented in our study is based on our research and literature data.

中文翻译：

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BaO-B2O3系统及其神秘成员Ba3B2O6

1949年对BaO–B ₂ O ₃系统和原硼酸钡Ba ₃ B ₂ O ₆（3BaO·B ₂ O ₃）进行了首次系统研究。此后，对该系统进行了反复精制，但Ba ₃ B ₂的结构O ₆化合物尚未得到充分研究。在我们的研究中，我们首次获得了Ba ₃ B ₂ O ₆的晶体样品。求解的结构（Pbam，a = 13.5923（4）Å，b = 13.6702（4）Å，c =14.8894（3）Å）具有伪四方[Ba ₁₂（BO ₃）₆ ] ⁶⁺阳离子图案，属于“反沸石”硼酸盐类别，该图案包含沿c轴填充阴离子簇的通道。Ba ₃ B ₂ O ₆化合物可被视为Ba ₃（BO ₃）_{2 – x} F _{3 x}固溶体的无氟端基。本研究中提出的BaO–B ₂ O ₃相图基于我们的研究和文献数据。