Thallium(III) oxide
Thallium(III) oxide
Other names
thallium trioxide, thallium sesquioxide
3D model (JSmol)
ECHA InfoCard 100.013.846 Edit this at Wikidata
EC Number
  • 215-229-3
  • InChI=1S/3O.2Tl/q3*-2;2*+3 checkY
  • [O-2].[O-2].[O-2].[Tl+3].[Tl+3]
Molar mass 456.76 g/mol
Appearance dark brown solid
Density 10.19 g/cm3, solid (22 °C)
Melting point 717 °C (1,323 °F; 990 K)
Boiling point 875 °C (1,607 °F; 1,148 K) (decomposes)
+76.0·10−6 cm3/mol
Cubic, (Bixbyite) cI80[2]
Ia3 (No. 206)
GHS labelling:[3]
GHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard
H300+H330, H373, H411
P273, P301+P310+P330, P304+P340+P310, P314
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
Lethal dose or concentration (LD, LC):
44 mg/kg (oral, rat)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Thallium(III) oxide, also known as thallic oxide, is a chemical compound of thallium and oxygen. It occurs in nature as the rare mineral avicennite.[4] Its structure is related to that of Mn2O3 which has a bixbyite like structure. Tl2O3 is metallic with high conductivity and is a degenerate n-type semiconductor which may have potential use in solar cells.[5] A method of producing Tl2O3 by MOCVD is known.[6] Any practical use of thallium(III) oxide will always have to take account of thallium's poisonous nature. Contact with moisture and acids may form poisonous thallium compounds.


It is produced by the reaction of thallium with oxygen or hydrogen peroxide in an alkaline thallium(I) solution. Alternatively, it can be created by the oxidation of thallium(I) nitrate by chlorine in an aqueous potassium hydroxide solution.[7]


  1. ^ Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, FL: CRC Press. p. B156. ISBN 0-8493-0462-8..
  2. ^ Otto H.H.; Baltrasch R.; Brandt H.J. (1993). "Further evidence for Tl3+ in Tl-based superconductors from improved bond strength parameters involving new structural data of cubic Tl2O3". Physica C. 215 (1–2): 205. doi:10.1016/0921-4534(93)90382-Z.
  3. ^ GHS: Sigma-Aldrich 204617
  4. ^ Handbook of Mineralogy
  5. ^ Phillips R. J.; Shane M. J.; Switzer J. A. (1989). "Electrochemical and photoelectrochemical deposition of Thallium(III) Oxide thin films". Journal of Materials Research. 4 (4): 923. doi:10.1557/JMR.1989.0923.
  6. ^ D. Berry; R. T. Holm; R. L. Mowery; N. H. Turner & M. Fatemi (1991). "Thallium(III) Oxide by Organometallic Chemical Vapor Deposition". Chemistry of Materials. 3 (1): 72–77. doi:10.1021/cm00013a019.
  7. ^ Georg Brauer; Handbuch der präparativen anorganischen Chemie, Band 2, S.884; ISBN 3-432-87813-3 (in German)