TUNGSTEN (IV) OXIDE

Synonym(s):Tungsten dioxide

CAS NO.：12036-22-5
Empirical Formula: O2W
Molecular Weight: 215.84
MDL number: MFCD00049709
EINECS: 234-842-7
SAFETY DATA SHEET (SDS)
Update Date: 2025-01-27 09:38:02

What is TUNGSTEN (IV) OXIDE?

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]

The Uses of TUNGSTEN (IV) OXIDE

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.

Properties of TUNGSTEN (IV) OXIDE

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
color	brown
Specific Gravity	12.11
Water Solubility	Soluble in acid and potassium hydroxide. Insoluble in water.
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 for TUNGSTEN (IV) OXIDE

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H335:Specific target organ toxicity, single exposure;Respiratory tract irritation
Precautionary Statement Codes	P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P304+P340:IF INHALED: Remove victim to fresh air and Keep at rest in a position comfortable for breathing. P405:Store locked up. P403+P233:Store in a well-ventilated place. Keep container tightly closed.