| Names | |
|---|---|
| IUPAC name Molybdenum(IV) oxide | |
| Other names Molybdenum dioxide Tugarinovite | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.038.746 |
| EC Number |
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| |
| |
| Properties | |
| MoO2 | |
| Molar mass | 127.94 g/mol |
| Appearance | brownish-violet solid |
| Density | 6.47 g/cm3 |
| Melting point | 1,100 °C (2,010 °F; 1,370 K) decomposes |
| insoluble | |
| Solubility | insoluble inalkalies,HCl,HF slightly soluble in hotH2SO4 |
| +41.0·10−6 cm3/mol | |
| Structure | |
| Distortedrutile (monoclinic) | |
| Octahedral (MoIV); trigonal (O−II) | |
| Hazards | |
| Flash point | Non-flammable |
| Related compounds | |
Otheranions | Molybdenum disulfide |
Othercations | Chromium(IV) oxide Tungsten(IV) oxide |
Relatedmolybdenumoxides | "Molybdenum blue" Molybdenum trioxide |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Molybdenum dioxide is thechemical compound with theformula MoO2. It is a violet-colored solid and is a metallic conductor. The mineralogical form of this compound is calledtugarinovite, and is only very rarely found.
It crystallizes in amonoclinic cell, and has a distorted rutile, (TiO2) crystal structure. In TiO2 theoxide anions areclose 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 251pm 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 adelocalisation of some of the Mo electrons in a conductance band accounting for the metallic conductivity.[1]
MoO2 can be prepared :
Single crystals are obtained bychemical transport usingiodine. Iodine reversibly converts MoO2 into the volatile species MoO2I2.[3]
Molybdenum dioxide is a constituent of "technical molybdenum trioxide" produced during the industrial processing ofMoS2:[4][5]
MoO2 has been reported as catalysing thedehydrogenation of alcohols,[6] the reformation of hydrocarbons[7] and biodiesel.[8] Molybdenum nano-wires have been produced by reducing MoO2 deposited on graphite.[9] Molybdenum dioxide has also been suggested as possible anode material forLi-ion batteries.[10][11]
