ThO2 — Properties & Data | MatWorld

ThO2

semiconductor

· ThO2

Thorium dioxide (ThO2) is a ceramic oxide compound classified as a wide-bandgap semiconductor material, notable for its high refractory nature and strong ionic bonding. Industrial applications span nuclear fuel elements (THOREX fuel cycles), high-temperature refractories for furnace linings and crucibles, and specialized optical coatings where its transparency in the infrared range is valued. Engineers select ThO2 over alternatives primarily for extreme-temperature stability, resistance to thermal shock, and its historical role in nuclear fuel development; however, its radioactive thorium content requires specialized handling and regulatory compliance, making it suitable only for applications where its unique thermal and chemical properties justify the associated constraints.

nuclear fuel elementshigh-temperature refractoriesfurnace linings and cruciblesinfrared optical coatingsarc-lamp cathodeswelding electrodes

Compliance & Regulations

?EAR?Conflict Free?RoHS?REACH?TSCA?Prop 65

Units:

Property	Value	Unit	Conditions	Source
Bulk Modulus(K)	28,238.8	ksi	—
Poisson's Ratio(ν)	0.3000	-	—
Shear Modulus(G)	13,740.9	ksi	—

Verified Unverified Low confidence (<80%) Link to source

Property	Value	Unit	Conditions	Source
Thermal Conductivity(k)	5.200 range 1.156–8.089median of 4 measurements	BTU/(hr·ft·°F)	—

Verified Unverified Low confidence (<80%) Link to source

Property	Value	Unit	Conditions	Source
Density(ρ)	0.3567	lb/in³	—

Verified Unverified Low confidence (<80%) Link to source

Property	Value	Unit	Conditions	Source
Band Gap(Eg)2 entries	3.500	eV	—
↳	4.823	eV	—
Dielectric Constant (Relative Permittivity)(εr)	20.31	-	—
Magnetic Moment(μB)	0.000	µB	—
Piezoelectric Modulus(eij)	0.000	C/m²	—
Seebeck Coefficient(S)	-463.7	µV/K	—

N entriesMultiple entries per property — large groups are collapsed; click a summary row to expand. Use filters above to narrow by form, heat treatment, basis, or test environment.

Verified Unverified Low confidence (<80%) Link to source

Property	Value	Unit	Conditions	Source
Energy Above Hull(ΔEhull)	0.000	eV/atom	—
Formation Energy(ΔHf)2 entries	-4.238	eV/atom	—
↳	-4.176	eV/atom	—

N entriesMultiple entries per property — large groups are collapsed; click a summary row to expand. Use filters above to narrow by form, heat treatment, basis, or test environment.

Verified Unverified Low confidence (<80%) Link to source

Regulatory Screening

Environmental

Export Control

RoHS, REACH, and Prop 65 statuses are validated against official substance lists (ECHA SVHC Candidate List, OEHHA Prop 65, RoHS Annex II). Other regulations are estimated from composition and material classification. All screening is a starting point for due diligence — always verify with your supplier before making compliance decisions.