Tungsten(IV) oxide

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| verifiedrevid = 448216913

| ImageFile = WO2structure.jpg

| ImageName = Tungsten(IV) oxide

| IUPACName =

| OtherNames = Tungsten dioxide

| Section1 = {{Chembox Identifiers

| CASNo = 12036-22-5

| CASNo_Ref = {{cascite|correct|CAS}}

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = 0Q43JGJ0GV

| PubChem = 82850

| EINECS = 234-842-7

| InChI = 1S/2O.W

| SMILES = O=[W]=O

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| Section2 = {{Chembox Properties

| Formula = WO₂

| MolarMass = 215.839 g/mol

| Appearance = Bronze solid

| Density = 10.8 g/cm³

| MeltingPtC = 1474

| MeltingPt_notes = from doi: 10.1007/BF02877593, decomposes at 1700 ◦C

| Solubility = Negligible

| MagSus = 5.7{{e|−5}} cm³/mol

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| Section3 = {{Chembox Structure

| CrystalStruct = Distorted rutile (monoclinic), mP12, space group P2₁/c, no 14

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| Section7 = {{Chembox Hazards

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| FlashPt = Non-flammable

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| Section8 = {{Chembox Related

| OtherAnions = Tungsten disulfide

| OtherCations = Chromium(IV) oxide
Molybdenum(IV) oxide

| OtherFunction = Tungsten(III) oxide
Tungsten(VI) oxide

| OtherFunction_label = tungsten oxides

| OtherCompounds =

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Tungsten(IV) oxide is the chemical compound with the formula WO₂. The bronze-colored solid crystallizes in a monoclinic cell.{{Wells5th}} The rutile-like structure features distorted octahedral WO₆ centers with alternate short W–W bonds (248 pm). 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.{{cite book |author1=Conroy, L. E. |author2=Ben-Dor, L. |chapter=Molybdenum(IV) Oxide and Tungsten(IV) Oxide Single Crystals | title = Inorganic Syntheses | series = Inorganic Syntheses | year = 1995 | volume = 30 | pages = 105–07 | doi = 10.1002/9780470132616.ch21|isbn=978-0-470-13261-6 }}{{cite book | last1 = Rogers | first1 = D. B. | last2 = Butler | first2 = S. R. | last3 = Shannon | first3 = R. D. | chapter = Single Crystals of Transition-Metal Dioxides | year = 1972 | title = Inorganic Syntheses | series = Inorganic Syntheses | volume = XIII | pages = 135–145 | doi = 10.1002/9780470132449.ch27 | isbn = 978-0-470-13244-9 }}