Substance profile
Antimony Trioxide
Antimony Trioxide is colorless, cubic form (valentinite); colorless (senarmontite) and is odorless.
01 · Identification
What Antimony Trioxide is
Antimony Trioxide is colorless, cubic form (valentinite); colorless (senarmontite) and is odorless. Its molecular formula is O3Sb2 and its molecular weight is 291.52 g/mol. It boils at 1425 °C, melts at 655 °C, is slightly soluble in water.
Under the GHS it carries the signal word Warning. It is classed as carcinogens.
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>. |
03 · Physical and chemical properties
Antimony 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 | 1425 °C (2597 °F) | HSDB | |
| 1425 °C (2597 °F) | at 760 mmHg | DOE PAC | |
| 1550 °C (2822 °F) | sublimes, at 760 mmHg | CAMEO | |
| Melting point | 655 °C (1211 °F) | HSDB | |
| 656 °C (1212.8 °F) | ICSC | ||
| Density | 5.67 g/cm³ | valentinite | HSDB |
| 5.9 g/cm³ | at 24 °C | ICSC | |
| 5.2 g/cm³ | at 25 °C | CAMEO | |
| Solubility | Slightly soluble in water | HSDB | |
| Very slightly soluble in water | HSDB | ||
| Soluble in KOH | HSDB | ||
| Vapor pressure | 1 mmHg | at 574 °C | HSDB |
| 1 mmHg | at 573.89 °C | CAMEO | |
| 0.9751 mmHg | at 574 °C | ICSC | |
| Flash point | Not Applicable. Not flammable. (USCG, 1999) | CAMEO | |
| Lower explosive limit (LEL) | Not Applicable. Not flammable. (USCG, 1999) | CAMEO | |
| Upper explosive limit (UEL) | Not Applicable. Not flammable. (USCG, 1999) | CAMEO |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Antimony Trioxide
Storage conditions
Safe Storage: Separated from food and feedstuffs.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Incompatible with chlorinated rubber and heat of 216 °C and with BrF3.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
ANTIMONY TRIOXIDE ignites and burns when heated in powdered form in air [Mellor 9:425 1946-47]. Reacts violently with bromine trifluoride [Mellor Vol. 9 425.1939].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Antimony Trioxide in the storage compatibility matrix →