Uranium trioxide

Uranium trioxide
Names
	IUPAC names Uranium trioxide; Uranium(VI) oxide
	Other names Uranyl oxide; Uranic oxide
Identifiers
CAS Number	1344-58-7 ;
3D model (JSmol)	Interactive image;
ChemSpider	66635;
ECHA InfoCard	100.014.274
EC Number	215-701-9;
PubChem CID	74013;
UNII	Q47SFG7DIQ ;
CompTox Dashboard (EPA)	DTXSID901014433 ;
	InChI InChI=1S/3O.U Key: JCMLRUNDSXARRW-UHFFFAOYSA-N;
	SMILES O=[U](=O)=O;
Properties
Chemical formula	UO3
Molar mass	286.29 g/mol
Appearance	yellow-orange powder
Density	5.5–8.7 g/cm3
Melting point	~200–650 °C (decomposes)
Solubility in water	insoluble
Structure
Crystal structure	see text
Space group	I41/amd (γ-UO3)
Thermochemistry
Std molar; entropy (S⦵298)	99 J·mol−1·K−1
Std enthalpy of; formation (ΔfH⦵298)	−1230 kJ·mol−1
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H330, H373, H411
NFPA 704 (fire diamond)	4 0 1 OX
Flash point	Non-flammable
Safety data sheet (SDS)	External MSDS
Related compounds
Related uranium oxides	Uranium dioxide; Triuranium octoxide
	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

Uranium trioxide (UO₃), also called uranyl oxide, uranium(VI) oxide, and uranic oxide, is the hexavalent oxide of uranium. The solid may be obtained by heating uranyl nitrate to 400 °C. Its most commonly encountered polymorph is amorphous UO₃.

^ ^a ^b Zumdahl SS (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.

[b1-1] Zumdahl SS (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.

[1]

Names

IUPAC names Uranium trioxide Uranium(VI) oxide
Other names Uranyl oxide Uranic oxide
Identifiers
CAS Number	1344-58-7^Y
3D model (JSmol)	Interactive image
ChemSpider	66635
ECHA InfoCard	100.014.274
EC Number	215-701-9
PubChem CID	74013
UNII	Q47SFG7DIQ^Y
CompTox Dashboard (EPA)	DTXSID901014433
InChI InChI=1S/3O.U Key: JCMLRUNDSXARRW-UHFFFAOYSA-N
SMILES O=[U](=O)=O
Properties
Chemical formula	UO₃
Molar mass	286.29 g/mol
Appearance	yellow-orange powder
Density	5.5–8.7 g/cm³
Melting point	~200–650 °C (decomposes)
Solubility in water	insoluble
Structure
Crystal structure	see text
Space group	I4₁/amd (γ-UO₃)
Thermochemistry
Std molar entropy (S^⦵₂₉₈)	99 J·mol⁻¹·K⁻¹^[1]
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	−1230 kJ·mol⁻¹^[1]
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H300, H330, H373, H411
NFPA 704 (fire diamond)	4 0 1 OX
Flash point	Non-flammable
Safety data sheet (SDS)	External MSDS
Related compounds
Related uranium oxides	Uranium dioxide Triuranium octoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references