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|Section2= |Section3=〔http://www.ehs.neu.edu/laboratory_safety/general_information/nfpa_hazard_rating/documents/NFPAratingJR.htm〕 |Section4= }} Pentaborane, also called pentaborane(9) to distinguish it from pentaborane(11) (B5H11), is an inorganic compound with the formula B5H9. It is one of the most common boron hydride clusters, although it is a highly reactive compound. Because of its high reactivity toward oxygen, it was once evaluated as rocket or jet fuel. Like many of the smaller boron hydrides, pentaborane is colourless, diamagnetic and volatile. ==Structure, synthesis, properties== Its structure is that of five atoms of boron arranged in a square pyramid. Each boron has a terminal hydride ligand and four hydrides span the edges of the base of the pyramid. It is classified as a nido cage. It was first prepared by Alfred Stock by pyrolysis of diborane at about 200 °C. An improved synthesis starts from salts of B3H8−, which is converted to the bromide B3H7Br− using is HBr. Pyrolysis of this bromide gives pentaborane. In the U.S., pentaborane was produced by Callery Chemical Company. Pentaborane is a colorless mobile liquid with a pungent odor (resembling garlic, acetylene, or sour milk). Above 150 °C, it decomposes, producing hydrogen; when it occurs in a closed container, the consequent rise of pressure can be dangerous. It is much more stable in presence of water than diborane. It is soluble in hydrocarbons, benzene, and cyclohexane, and in greases including those used in lab equipment. In storage, it decomposes negligibly, yielding a small amount of hydrogen and solid residue. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pentaborane」の詳細全文を読む スポンサード リンク
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