无定形固体
拉曼光谱
微晶
五氧化二铁
红外光谱学
正交晶系
氢键
多形性
氧化钒
氧化物
化学
红外线的
结晶学
材料科学
分析化学(期刊)
钒
无机化学
有机化学
晶体结构
分子
光学
物理
作者
Clément Sánchez,Jacques Livage,G. Lucazeau
标识
DOI:10.1002/jrs.1250120110
摘要
Abstract Amorphous V 2 O 5 can be obtained by cooling from the melt. This amorphous oxide is very sensitive to water vapour and can even be dissolved in water to give a vanadium pentoxide gel. The hydration process has been followed by infrared and Raman spectroscopy between 20 and 4000 cm −1 . Short‐range order in the amorphous oxide appears to be almost the same as in orthorhombic V 2 O 5 . The amorphous phase could even be described as made of small crystallites about 100 Å in diameter. The structure of amorphous V 2 O 5 does not seem to be modified by water adsorption, at least during the first stages of the hydration process. However, a drastic modification occurs when enough water is added to give a gel. A general shift to lower frequencies is observed, indicating a weakening of the VO bonds, presumably associated with the formation of new VOH 2 bonds. Two different water species have been identified, one of which seems to be almost free of hydrogen bonding. Short‐range order in the gels seems to be quite well defined and the spectra could be interpreted either in terms of crystallites, as in amorphous V 2 O 5 , or in terms of molecular (or macromolecular) species containing V 2 O 5 , (H 2 O), groups.
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