Tungsten(IV) oxide

Tungsten(IV) oxide
Names
	Other names Tungsten dioxide
Identifiers
CAS Number	12036-22-5 ;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.031.662
EC Number	234-842-7;
PubChem CID	82850;
UNII	0Q43JGJ0GV ;
CompTox Dashboard (EPA)	DTXSID0065195 ;
	InChI InChI=1S/2O.W;
	SMILES O=[W]=O;
Properties
Chemical formula	WO2
Molar mass	215.839 g/mol
Appearance	Bronze solid
Density	10.8 g/cm3
Melting point	1,474 °C (2,685 °F; 1,747 K) from doi: 10.1007/BF02877593, decomposes at 1700 ◦C
Solubility in water	Negligible
Magnetic susceptibility (χ)	5.7×10−5 cm3/mol
Structure
Crystal structure	Distorted rutile, (monoclinic), mP12, space group P21/c, no 14
Hazards
Flash point	Non-flammable
Related compounds
Other anions	Tungsten disulfide
Other cations	Chromium(IV) oxide; Molybdenum(IV) oxide
Related tungsten oxides	Tungsten(III) oxide; Tungsten(VI) oxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Tungsten(IV) oxide is the chemical compound with the formula W O₂. The bronze-colored solid crystallizes in a monoclinic cell.^[1] The rutile-like structure features distorted octahedral WO₆ centers with alternate short W–W bonds (248 pm).^[1] Each tungsten center has the d² configuration, which gives the material a high electrical conductivity.

WO₂ is prepared by reduction of WO₃ with tungsten powder over the course of 40 hours at 900 °C. An intermediate in this reaction is the partially reduced, mixed valence species W₁₈O₄₉.

2 WO₃ + W → 3 WO₂

The molybdenum analogue MoO₂ is prepared similarly. Single crystals are obtained by chemical transport technique using iodine. Iodine transports the WO₂ in the form of the volatile species WO₂I₂.^[2]^[3]

References

^ ^a ^b Wells, A. F. (1984), Structural Inorganic Chemistry (5th ed.), Oxford: Clarendon Press, ISBN 0-19-855370-6
^ Conroy, L. E.; Ben-Dor, L. (1995). "Molybdenum(IV) Oxide and Tungsten(IV) Oxide Single Crystals". Inorganic Syntheses. Inorganic Syntheses. Vol. 30. pp. 105–07. doi:10.1002/9780470132616.ch21. ISBN 978-0-470-13261-6.
^ Rogers, D. B.; Butler, S. R.; Shannon, R. D. (1972). "Single Crystals of Transition-Metal Dioxides". Inorganic Syntheses. Inorganic Syntheses. Vol. XIII. pp. 135–145. doi:10.1002/9780470132449.ch27. ISBN 978-0-470-13244-9.

This inorganic compound–related article is a stub. You can help Wikipedia by expanding it.

[Wells-1] Wells, A. F. (1984), Structural Inorganic Chemistry (5th ed.), Oxford: Clarendon Press, ISBN 0-19-855370-6

[2] Conroy, L. E.; Ben-Dor, L. (1995). "Molybdenum(IV) Oxide and Tungsten(IV) Oxide Single Crystals". Inorganic Syntheses. Inorganic Syntheses. Vol. 30. pp. 105–07. doi:10.1002/9780470132616.ch21. ISBN 978-0-470-13261-6.

[3] Rogers, D. B.; Butler, S. R.; Shannon, R. D. (1972). "Single Crystals of Transition-Metal Dioxides". Inorganic Syntheses. Inorganic Syntheses. Vol. XIII. pp. 135–145. doi:10.1002/9780470132449.ch27. ISBN 978-0-470-13244-9.

[1]

[2]

[3]