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|Section2= |Section3= |Section4= |Section7= |Section8= }} Molybdenum dioxide is the chemical compound with the formula MoO2. It is a violet-colored solid and is a metallic conductor. It crystallizes in a monoclinic cell, and has a distorted rutile, (TiO2) crystal structure. In TiO2 the oxide anions are close packed and titanium atoms occupy half of the octahedral interstices (holes). In MoO2 the octahedra are distorted, the Mo atoms are off-centre, leading to alternating short and long Mo – Mo distances and Mo-Mo bonding. The short Mo – Mo distance is 251 pm which is less than the Mo – Mo distance in the metal, 272.5 pm. The bond length is shorter than would be expected for a single bond. The bonding is complex and involves a delocalisation of some of the Mo electrons in a conductance band accounting for the metallic conductivity.〔''Oxides: Solid state chemistry'' McCarroll W.H. Encyclopedia of Inorganic Chemistry Ed R. Bruce King, (1994), John Wiley & sons ISBN 0-471-93620-0〕 MoO2 can be prepared : *by reduction of MoO3 with Mo over the course of 70 hours at 800 °C. The tungsten analogue, WO2, is prepared similarly. :2 MoO3 + Mo *by reducing MoO3 with H2 or NH3 below 470 °C Single crystals are obtained by chemical transport using iodine. Iodine reversibly converts MoO2 into the volatile species MoO2I2.〔Conroy, L. E.; Ben-Dor, L. "Molybdenum(IV) Oxide and Tungsten(IV) Oxides Single-Crystals" Inorganic Syntheses 1995, volume 30, pp. 105–107. ISBN 0-471-30508-1〕 Molybdenum oxide is a constituent of "technical molybdenum oxide" produced during the industrial processing of MoS2:〔''Metallurgical furnaces'' Jorg Grzella, Peter Sturm, Joachim Kruger, Markus A. Reuter, Carina Kogler, Thomas Probst, Ullmans Encyclopedia of Industrial Chemistry〕〔"Thermal Analysis and Kinetics of Oxidation of Molybdenum Sulfides" Y. Shigegaki, S.K. Basu, M.Wakihara and M. Taniguchi, J. Therm. Analysis 34 (1988), 1427-1440〕 :2 MoS2 + 7O2 :MoS2 + 6MoO3 :2 MoO2 + O2 MoO2 has been reported as catalysing the dehydrogenation of alcohols,〔A. A. Balandin and I. D. Rozhdestvenskaya, Russian Chemical Bulletin, 8, 11, (1959), 1573 〕 the reformation of hydrocarbons〔''Molybdenum based catalysts. I. MoO2 as the active species in the reforming of hydrocarbons'' A. Katrib, P. Leflaive, L. Hilaire and G. Maire Catalysis Letters, 38, 1–2, (1996) 〕 and biodiesel.〔Catalytic partial oxidation of a biodiesel surrogate over molybdenum dioxide, C.M. Cuba-Torres, et al, Fuel (2015), 〕 Molybdenum nano-wires have been produced by reducing MoO2 deposited on graphite〔''Synthesis of Molybdenum Nanowires with Millimeter-Scale Lengths Using Electrochemical Step Edge Decoration'' M. P. Zach, K. Inazu, K. H. Ng, J. C. Hemminger, and R. M. Penner Chem. Mater. (2002),14, 3206 〕 Mineralogical form of this compound is called tugarinovite, only very rarely found. ==References== 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「Molybdenum(IV) oxide」の詳細全文を読む スポンサード リンク
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