TUNGSTEN (IV) OXIDE Chemical Properties

Melting point:

1500-1600°C

Boiling point:

1730℃[at 101 325 Pa]

Density 

12,11 g/cm³

solubility 

insoluble in H2O, organic solvents

form 

Powder

Specific Gravity

12.11

color 

brown

Water Solubility 

Soluble in acid and potassium hydroxide. Insoluble in water.

Crystal Structure

MoO2 type

crystal system

Monoclinic

Space group

P21/c

Lattice constant

a/nm	b/nm	c/nm	α/o	β/o	γ/o	V/nm3
0.5563	0.4896	0.5663	90	120.657	90	0.1327

Exposure limits

ACGIH: TWA 3 mg/m3
NIOSH: TWA 5 mg/m3; STEL 10 mg/m3

CAS DataBase Reference

12036-22-5(CAS DataBase Reference)

EPA Substance Registry System

Tungsten oxide (WO2) (12036-22-5)

Safety Information

Hazard Codes 

Xi

Risk Statements 

37

Safety Statements 

26-36

WGK Germany 

3

TSCA 

Yes

MSDS

• Language:English Provider:SigmaAldrich
• Language:English Provider:ALFA

TUNGSTEN (IV) OXIDE Usage And Synthesis

Description

Tungsten(IV) oxide, WO2, is a bronze-colored solid that crystallizes in a monoclinic cell. 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 in about 40 h at 900℃. An intermediate in this reaction is the partially reduced, mixed valence species W18O49.
 2WO3 + W→3WO2

Chemical Properties

brown powder(s), may become purple on standing; formed when WO3 is reduced by H2 at 575°C–600°C [KIR83] [STR93]

Uses

Tungsten(IV) oxide is used in the production of tungsten and tungstates, in alloys, in fire-proofing fabrics and as a ceramic pigment. It is used to study their chromism, photocatalysis and sensing capabilities. It is associated with rhenium trioxide particles and used for detection of protonatable, radical and precharged species under laser desorption ionization.

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