Niobium dioxide
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IUPAC name
niobium(IV) oxide, niobium dioxide
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Other names
niobium(IV) oxide, columbium dioxide
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Identifiers | |
3D model (
JSmol ) |
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ECHA InfoCard
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100.031.632 |
EC Number |
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PubChem CID
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CompTox Dashboard (EPA)
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Properties | |
NbO2 | |
Molar mass | 124.91 g/mol |
Appearance | bluish black solid |
Melting point | 1,915 °C (3,479 °F; 2,188 K)[1] |
Structure | |
Tetragonal, tI96
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I41/a, No. 88 | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Niobium dioxide, is the
Properties
The room temperature form of NbO2 has a tetragonal, rutile-like structure with short Nb-Nb distances, indicating Nb-Nb bonding.[3] The high temperature form also has a rutile-like structure with short Nb-Nb distances.[4] Two high-pressure phases have been reported: one with a rutile-like structure (again, with short Nb-Nb distances); and a higher pressure with baddeleyite-related structure.[5]
NbO2 is insoluble in water and is a powerful reducing agent, reducing carbon dioxide to carbon and sulfur dioxide to sulfur.[1] In an industrial process for the production of niobium metal, NbO2 is produced as an intermediate, by the hydrogen reduction of Nb2O5.[6] The NbO2 is subsequently reacted with magnesium vapor to produce niobium metal.[7]
References
- ^ ISBN 0-8493-6071-4
- ISBN 0-07-049439-8
- ISBN 0-19-855370-6
- .
- hdl:10183/198788.
- ^ Patent EP1524252, Sintered bodies based on niobium suboxide, Schnitter C, Wötting G
- ^ Method for producing tantalum/niobium metal powders by the reduction of their oxides by gaseous magnesium, US patent 6171363 (2001), Shekhter L.N., Tripp T.B., Lanin L.L. (H. C. Starck, Inc.)