A new aluminum borate, Ba[AlB₄O₈(OH)], has been synthesized under high-temperature, high-pressure hydrothermal conditions at 550 °C and 1400 bar and its structure characterized by single-crystal X-ray diffraction, IR, and MAS ¹¹B, and ²⁷Al NMR spectroscopy. It crystallizes in the monoclinic space group P2₁/n with a = 7.0695(5) Å, b = 15.108(1) Å, c = 7.0746(5) Å, β = 93.593(2)°, and Z = 4. Its 2D layer structure is formed of corner-sharing B₄O₈(OH) clusters and AlO₄ tetrahedra with the charge-compensating Ba²⁺ cations between the layers. While the same in the framework composition, the title compound and the hydrate, Ba[AlB₄O₈(OH)]·H₂O, differ greatly in structure. Although the title compound contains an OH group, it is thermally stable up to 740 °C and then decomposes into Ba₂Al₂B₈O₁₇, as indicated by high-temperature DSC/TG analysis and powder X-ray diffraction.

中文翻译：

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硼酸铝Ba [AlB ₄ O ₈（OH）]的高温高压水热合成，晶体结构，热稳定性和固态NMR光谱

一种新型的硼酸铝Ba [AlB ₄ O ₈（OH）]是在高温高压水热条件下，550°C和1400 bar下合成的，其结构具有单晶X射线衍射，IR的特征。 ，以及MAS ¹¹ B和²⁷ Al NMR光谱。它结晶单斜晶系空间群P 2 ₁ / Ñ与一个= 7.0695（5），b = 15.108（1）埃，c ^ = 7.0746（5），β= 93.593（2）°，Ž = 4。它的2D层结构由边角共享B ₄ O ₈（OH）簇和AlO _4组成在层之间具有电荷补偿Ba ²⁺阳离子的四面体。尽管骨架组成相同，但标题化合物和水合物Ba [AlB ₄ O ₈（OH）]·H ₂ O的结构差异很大。尽管标题化合物含有OH基，但是如高温DSC / TG分析和粉末X射线衍射所示，其在高达740℃下是热稳定的，然后分解为Ba ₂ Al ₂ B ₈ O ₁₇。