Thulium(III) oxide

Thulium(III) oxide is a pale green crystalline compound, with the formula Tm₂O₃. It was first isolated in 1879, from an impure sample of erbia, by Swedish chemist Per Teodor Cleve, who named it thulia.

Thulium(III) oxide

Thulium(III) oxide
Names
IUPAC name Thulium(III) oxide
Other names Thulium oxide, thulium sesquioxide
Identifiers
CAS Number	12036-44-1 Y
3D model (JSmol)	Interactive image
ECHA InfoCard	100.031.670
EC Number	234-851-6
PubChem CID	159411
UNII	DZJ5EE05EB Y
CompTox Dashboard (EPA)	DTXSID50894774
InChI InChI=1S/3O.2Tm/q3*-2;2*+3
SMILES [O-2].[O-2].[O-2].[Tm+3].[Tm+3]
Properties
Chemical formula	Tm2O3
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)
Solubility	Slightly soluble in acids
Magnetic susceptibility (χ)	+51,444·10−6 cm3/mol
Structure
Crystal structure	Cubic, cI80[1]
Space group	Ia-3, No. 206[1]
Lattice constant	a = 10.49 Å[1]
Formula units (Z)	16[1]
Thermochemistry
Heat capacity (C)	2.515 °Cp[2] (25 °C)
Hazards
GHS labelling:
Pictograms
Safety data sheet (SDS)	Sigma-Aldrich
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). N verify (what is YN ?) Infobox references

Synthesis

Thulium(III) oxide has been made in the laboratory using various methods. One method involves burning thulium metal or its various salts in air.^[3][2]

Thulium(III) oxide can be made using a hydrothermal method where thulium(III) acetate is mixed with an ammonia solution, which causes thulium(III) oxide to precipitate as a white solid.^[1]

Properties

Thulium(III) oxide (Tm₂O₃) is a pale green, thermally stable powder with a high melting point of 2,341 °C and a density of 8.6 g/cm³, typically forming a cubic crystal structure.^[4] It is resistant to oxidation and dissolves in strong acids like hydrochloric acid, allowing it to form soluble thulium salts.^[5] Due to its unique f-electron configuration, Tm₂O₃ has notable optical properties.^[6] Thulium oxide (Tm₂O₃) is considered fibrogenic; it has the potential to induce tissue injury and fibrosis when inhaled or otherwise introduced to biological tissue.^[7]