Substance profile
Molybdenum trioxide
Molybdenum trioxide is white or slightly yellow to slightly bluish powder or granules with a none odor.
01 · Identification
What Molybdenum trioxide is
Molybdenum trioxide is white or slightly yellow to slightly bluish powder or granules with a none odor. Its molecular formula is MoO3 and its molecular weight is 143.95 g/mol. It boils at 1155 °C, melts at 795 °C.
Under the GHS it carries the signal word Warning.
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 |
|---|---|
| H351 | Suspected of causing cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H335 | May cause respiratory irritation. |
| H319 | Causes serious eye irritation. |
Precautionary statements: P201, P264, P280, P305, P308, P313, P337, P338
03 · Physical and chemical properties
Molybdenum trioxide 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 | 1155 °C (2111 °F) | at 760 mmHg | DOE PAC |
| 1155 °C (2111 °F) | sublimes | HSDB | |
| 1155 °C (2111 °F) | sublimes, at 760 mmHg | CAMEO | |
| Melting point | 795 °C (1463 °F) | HSDB | |
| 802 °C (1475.6 °F) | DOE PAC | ||
| Density | 4.69 g/cm³ | at 20 °C | CAMEO |
| 4.696 g/cm³ | at 25 °C | DOE PAC | |
| 4.69 g/cm³ | at 26 °C | HSDB | |
| Solubility | After strong ignition it is very slightly sol in acids | HSDB | |
| Sol in concentrated mineral acids | HSDB | ||
| Sol in soln of alkali hydroxides and soln of potassium bitartrate | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Molybdenum trioxide
Incompatible materials
/Incompatible with/ alkali metals; sodium, potassium, molten magnesium. /Molybdenum, sol compounds, (as Mo)/
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
MOLYBDENUM TRIOXIDE reacts violently with chlorine trifluoride, lithium, potassium and sodium. Readily combines with acids and bases to form a series of polymeric compounds. Incompatible with interhalogens and metals. A violent detonation occurs when heated with molten magnesium. (NTP, 1992)
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Molybdenum trioxide in the storage compatibility matrix →