Thulium(III) oxide
Thulium(III) oxide
Other names
Thulium oxide, thulium sesquioxide
3D model (JSmol)
ECHA InfoCard 100.031.670 Edit this at Wikidata
  • InChI=1S/3O.2Tm/q3*-2;2*+3
  • [O-2].[O-2].[O-2].[Tm+3].[Tm+3]
Molar mass 385.866 g/mol
Appearance greenish-white cubic crystals
Density 8.6 g/cm3
Melting point 2,341 °C (4,246 °F; 2,614 K)
Boiling point 3,945 °C (7,133 °F; 4,218 K)
slightly soluble in acids
+51,444·10−6 cm3/mol
Cubic, cI80
Ia-3, No. 206
Related compounds
Other anions
Thulium(III) chloride
Other cations
Erbium(III) oxide
Ytterbium(III) oxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Thulium(III) oxide is a pale green solid compound, with the formula Tm2O3. It was first isolated in 1879 from an impure sample of erbia by Per Teodor Cleve, who named it thulia. It can be prepared in the laboratory by burning thulium metal in air, or by decomposition of their oxoacid salts, such as thulium nitrate.[1]


  1. ^ Catherine E. Housecroft; Alan G. Sharpe (2008). "Chapter 25: The f-block metals: lanthanoids and actinoids". Inorganic Chemistry, 3rd Edition. Pearson. p. 864. ISBN 978-0-13-175553-6.