Terbium(III) oxide

Terbium(III) oxide
Names
	IUPAC name terbium(III) oxide
	Other names terbium trioxide, terbia, terbium sesquioxide
Identifiers
CAS Number	12036-41-8 ;
3D model (JSmol)	Interactive image;
ECHA InfoCard	100.031.668
EC Number	234-849-5;
PubChem CID	159410;
CompTox Dashboard (EPA)	DTXSID401014252 DTXSID40276469, DTXSID401014252 ;
	InChI InChI=1/3O.2Tb/q3-2;2+3;
	SMILES [O-2].[O-2].[O-2].[Tb+3].[Tb+3];
Properties
Chemical formula	O3Tb2
Molar mass	365.848 g·mol−1
Appearance	white crystals
Density	7.91 g/cm3
Melting point	2,410 °C (4,370 °F; 2,680 K)
Magnetic susceptibility (χ)	0.07834 cm3/mol
Structure
Crystal structure	Cubic, cI80
Space group	Ia3, No. 206
Lattice constant	a = 1.057 nm
Thermochemistry
Std molar; entropy (S⦵298)	156.90 J/mol·K
Std enthalpy of; formation (ΔfH⦵298)	-1865.23 kJ/mol
Gibbs free energy (ΔfG⦵)	-1776.553 kJ/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H319, H410
Precautionary statements	P264, P273, P280, P305+P351+P338, P337+P313, P391, P501
Related compounds
Other anions	Terbium(III) chloride
Other cations	Gadolinium(III) oxide; Dysprosium(III) oxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Terbium(III) oxide, also known as terbium sesquioxide, is a sesquioxide of the rare earth metal terbium, having chemical formula Tb
₂O
₃. It is a p-type semiconductor, which conducts protons, which is enhanced when doped with calcium.^[3] It may be prepared by the reduction of Tb
₄O
₇ in hydrogen at 1300 °C for 24 hours.^[4]

Tb₄O₇ + H₂ → 2 Tb₂O₃ + H₂O

It is a basic oxide and easily dissolved to dilute acids, and then almost colourless terbium salt is formed.

Tb₂O₃ + 6 H⁺ → 2 Tb³⁺ + 3 H₂O

The crystal structure is cubic and the lattice constant is a = 1057 pm.^[5]

^ Curzon A.E.; Chlebek H.G. (1973). "The observation of face centred cubic Gd, Tb, Dy, Ho, Er and Tm in the form of thin films and their oxidation". J. Phys. F. 3 (1): 1–5. Bibcode:1973JPhF....3....1C. doi:10.1088/0305-4608/3/1/009.
^ ^a ^b ^c R. Robie, B. Hemingway, and J. Fisher, "Thermodynamic Properties of Minerals and Related Substances at 298.15K and 1bar Pressure and at Higher Temperatures," US Geol. Surv., vol. 1452, 1978.[1]
^ Reidar Haugsrud; Yngve Larring & Truls Norby (December 2005). "Proton conductivity of Ca-doped Tb
₂O
₃". Solid State Ionics. 176 (39–40). Elsevier B.V.: 2957–2961. doi:10.1016/j.ssi.2005.09.030.
^ G. J. McCarthy (October 1971). "Crystal data on C-type terbium sesquioxide (Tb
₂O
₃)". Journal of Applied Crystallography. 4 (5): 399–400. doi:10.1107/S0021889871007295.
^ N. C. Baenzinger, H. A. Eick, H. S. Schuldt, L. Eyring: Terbium Oxides. III. X-Ray Diffraction Studies of Several Stable Phases. In: Journal of the American Chemical Society, 1961, 83, 10, S. 2219-23.

[1] Curzon A.E.; Chlebek H.G. (1973). "The observation of face centred cubic Gd, Tb, Dy, Ho, Er and Tm in the form of thin films and their oxidation". J. Phys. F. 3 (1): 1–5. Bibcode:1973JPhF....3....1C. doi:10.1088/0305-4608/3/1/009.

[usgs-2] R. Robie, B. Hemingway, and J. Fisher, "Thermodynamic Properties of Minerals and Related Substances at 298.15K and 1bar Pressure and at Higher Temperatures," US Geol. Surv., vol. 1452, 1978.[1]

[3] Reidar Haugsrud; Yngve Larring & Truls Norby (December 2005). "Proton conductivity of Ca-doped Tb
₂O
₃". Solid State Ionics. 176 (39–40). Elsevier B.V.: 2957–2961. doi:10.1016/j.ssi.2005.09.030.

[4] G. J. McCarthy (October 1971). "Crystal data on C-type terbium sesquioxide (Tb
₂O
₃)". Journal of Applied Crystallography. 4 (5): 399–400. doi:10.1107/S0021889871007295.

[Baenzinger-5] N. C. Baenzinger, H. A. Eick, H. S. Schuldt, L. Eyring: Terbium Oxides. III. X-Ray Diffraction Studies of Several Stable Phases. In: Journal of the American Chemical Society, 1961, 83, 10, S. 2219-23.

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