Tungsten oxide , ≥100 mesh, 99.9%metalsbasis , 12036-22-5

Synonym(s):
Tungsten dioxide

CAS NO.：12036-22-5

Empirical Formula: O2W

Molecular Weight: 215.84

MDL number: MFCD00049709

EINECS: 234-842-7

PRODUCT 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: 0.5563
  • b/nm: 0.4896
  • c/nm: 0.5663
  • α/o: 90
  • β/o: 120.657
  • γ/o: 90
  • V/nm3: 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)

Description and Uses

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

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.

Safety

• Symbol(GHS): GHS07
• Signal word: Warning
• Hazard statements: H335
• Precautionary statements: P261-P304+P340-P312a-P403+P233-P405-P501a
• Hazard Codes: Xi
• Risk Statements: 37
• Safety Statements: 26-36
• WGK Germany: 3
• TSCA: Yes