Uranium trioxide
Uranium trioxide (UO3), also called uranyl oxide, uranium(VI) oxide, and uranic oxide, is an oxide of uranium. UO3 is a hexavalent oxide, which means that the uranium in the compound has an oxidation state of +6. It can be formed by heating uranyl nitrate to 400 °C.
| Uranium trioxide | |
|---|---|
| |
| IUPAC name | Uranium trioxide Uranium(VI) oxide |
| Other names | Uranyl oxide Uranic oxide |
| Identifiers | |
| CAS number | |
| Properties | |
| Molecular 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 | Partially soluble |
| Structure | |
| Crystal structure | see text |
| Space group | I41/amd (γ-UO3) |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−1230 kJ·mol−1[1] |
| Standard molar entropy S |
99 J·mol−1·K−1[1] |
| Hazards | |
| EU classification | Very toxic (T+) Dangerous for the environment (N) |
| NFPA 704 |
0
4
1
|
| R-phrases | R26/28, R33, R51/53 |
| S-phrases | (S1/2), S20/21, S45, S61 |
| Flash point | Non-flammable |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) | |
UO3 is a poisonous and slightly radioactive substance. It can be harmful if it is breathed in, ingested, or makes contact with skin.
Uranium Trioxide Media
Methods of forming uranium trioxide
UO3 alpha form of the solid
UO3 beta form of the solid
Uranium trioxide (UO3) gamma lattice
environment of one of the uraniums in gamma uranium trioxide
Chains of U2O2 rings in gamma uranium trioxide
Lattice of uranium trioxide solid, drawn by cadmium using POVray using public domain data to drive the software used to write the pov file.
Ball and stick model of epsilon UO3
The calculated geometry of molecular uranium trioxide has C2v symmetry.
References
- ↑ 1.0 1.1 Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.
