Substance profile
Uranium
Uranium is a silver-white, malleable, ductile, lustrous solid.
01 · Identification
What Uranium is
Uranium is a silver-white, malleable, ductile, lustrous solid. Its molecular formula is U and its molecular weight is 238.029 g/mol. It boils at 4131 °C, melts at 1135 °C.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 3rd degree.
02 · GHS classification
Hazards and label elements
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
| Code | Hazard statement |
|---|---|
| H330 | Fatal if inhaled. |
| H300 | Fatal if swallowed. |
| H373 | May cause damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H413 | May cause long lasting harmful effects to aquatic life. |
Precautionary statements: P260, P270, P271, P273, P301, P304, P310, P314, P330, P501
03 · Physical and chemical properties
Uranium properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 4131 °C (7467.8 °F) | HSDB | |
| 3813 °C (6895 °F) | NIOSH | ||
| 4131 °C (7468 °F) | OSHA | ||
| Melting point | 1135 °C (2075 °F) | HSDB | |
| 1147 °C (2097 °F) | NIOSH | ||
| Density | 19.1 g/cm³ | HSDB | |
| 19.05 g/cm³ | metal | NIOSH | |
| 19.1 g/cm³ | at 25 °C | DOE PAC | |
| Solubility | Insol in water, alkalis, alcohol; soluble in acids | HSDB | |
| Insoluble | NIOSH | ||
| Vapor pressure | 0 mmHg | approx | NIOSH |
| 0 mmHg | at 20 °C | HSDB | |
| Autoignition temperature | 20 °C (68 °F) | cloud | HSDB |
| Lower explosive limit (LEL) | Minimum explosive concn 60 g/cu m | for dust | HSDB |
| A dust cloud of uranium metal dust may ignite explosively at ordinary temperatures. | HSDB | ||
| Uranium is pyrophoric ... | HSDB | ||
| Vapor density | 19.05 (air = 1) | metal | OSHA |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Source notes
Further notes on Uranium
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Solubility
Rapidly soluble in aqueous HCl. Non-oxidizing acids, such as sulfuric, phosphoric and hydrofluoric /acid/, react only very slowly with uranium; nitric acid dissolves massive uranium at a moderate rate.
Source: HSDB
05 · Handling and storage
Storing and handling Uranium
Storage conditions
Finely divided uranium metal is highly reactive or pyrophoric, capable of igniting spontaneously. This type of material should be handled and stored in a manner that minimizes fire potential. Typically, machining chips are stored under water or machining oil in open storage containers so that any H2 generated does not accumulate.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Uranium reacts with incandescence with hot selenium or sulfur (boiling).
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Uranium in the storage compatibility matrix →