Vanadium Oxide - Vanadium Oxide

[ I ] Vanadium(II) oxide: VO (66.94). Also known as vanadium monoxide. Obtained by reducing V ₂ O ₅ with K or by heating a mixture of VCl ₃ O and H ₂ over red-hot carbon. Gray powder crystal with metallic luster. Density 5.45 g cm ^-3 . Electrically conductive. Insoluble in water. Dissolves in mineral acids to form an aqueous solution of V ^Ⅱ . There is a considerable tendency for non-stoichiometric compounds, with VO _1-0.25 to VO _1+0.20 being obtained. [CAS 12035-98-2] [ II ] Vanadium(III) oxide: V ₂ O ₃ (149.88). Also known as divanadium trioxide. Obtained by reducing V ₂ O ₅ with red heat and H ₂ or CO. Black powder crystal. Density 4.87 g cm ^-3 . Melting point 1970 °C. It is electrically conductive with a resistivity of 55× ¹⁰⁻⁴⁶ Ω m (1100 °C). It is completely basic. It is slightly soluble in water. It dissolves in acid to become aqua ion [V(H ₂ O) ₆ ] ³⁺ (blue color), and when ^OH- is added to this, it produces a hydrated oxide, which is very easily oxidized in air. It is also soluble in alkali. It burns when heated in air. It is used as a hydrogenation catalyst. [CAS 1314-34-7] [ Ⅲ ] Vanadium oxide (IV): VO ₂ (82.94). It is also called vanadium dioxide. It is obtained by melting and reducing V ₂ O ₅ with oxalic acid, then heating it to red heat in the absence of air. It is a black to dark blue powdery crystal. Its density is 4.34 g cm ⁻³ . Its melting point is 1940 °C. It is amphoteric and easily soluble in acids and alkalis. At room temperature it is a semiconductor, but at 68°C it reversibly becomes metallic, and shows rapid changes in electrical conductivity and infrared reflectance. It changes color from yellow to green to blue depending on the temperature. It is used in temperature-controllable glass thin film materials, photocatalysts, etc. [CAS 12036-21-4] [ IV ] Vanadium oxide (V): V ₂ O ₅ (181.88). It is also called divanadium pentoxide. [CAS 1314-62-1]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

【Ⅰ】酸化バナジウム(Ⅱ)：VO(66.94)．一酸化バナジウムともいう．V₂O₅をKで還元するか，またはVCl₃Oと H₂ の混合物を赤熱炭素上で熱すると得られる．灰色の金属光沢をもつ粉末結晶．密度5.45 g cm^－3．電気伝導性を有する．水に不溶．鉱酸に溶け，V^Ⅱの水溶液となる．非化学量論的化合物としての傾向がかなりあり，VO_1－0.25～VO_1＋0.20が得られている．[CAS 12035-98-2]【Ⅱ】酸化バナジウム(Ⅲ)：V₂O₃(149.88)．三酸化二バナジウムともいう．V₂O₅を赤熱して H₂ またはCOで還元すると得られる．黒色の粉末結晶．密度4.87 g cm^－3．融点1970 ℃．電気伝導性があり，抵抗率55×10^－46 Ω m(1100 ℃)．完全に塩基性である．水に微溶．酸に溶けてアクアイオン [V(H₂O)₆]^3＋(青色)になり，これにOH^－を加えると水和した酸化物を生じ，空気中できわめて容易に酸化される．アルカリにも可溶．空気中で熱すると燃える．水素添加触媒に用いられる．[CAS 1314-34-7]【Ⅲ】酸化バナジウム(Ⅳ)：VO₂(82.94)．二酸化バナジウムともいう．V₂O₅をシュウ酸で融解還元したのち，空気を断って赤熱すると得られる．黒ないし暗青色の粉末状結晶．密度4.34 g cm^－3．融点1940 ℃．両性で，酸，アルカリに易溶．常温では半導体であるが，68 ℃ において可逆的に金属的となり，電気伝導率や赤外光反射率の急激な変化を示す．温度により黄-緑-青色に変化する．温度調光ガラス薄膜材料，光触媒などに用いられる．[CAS 12036-21-4]【Ⅳ】酸化バナジウム(Ⅴ)：V₂O₅(181.88)．五酸化二バナジウムともいう．[CAS 1314-62-1]

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