Substance profile
Arsenic
Arsenic is it exists in three allotropic forms, the yellow (alpha), black (beta) and grey (gamma) forms and is odorless.
01 · Identification
What Arsenic is
Arsenic is it exists in three allotropic forms, the yellow (alpha), black (beta) and grey (gamma) forms and is odorless. Its molecular formula is As and its molecular weight is 74.922 g/mol. It boils at 613 °C, melts at 613 °C, is practically insoluble in water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
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 |
|---|---|
| H331 | Toxic if inhaled. |
| H301 | Toxic if swallowed. |
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
Precautionary statements: P260, P270, P271, P273, P301, P304, P310, P330, P391, P501
03 · Physical and chemical properties
Arsenic 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 | 612.78 °C (1135 °F) | sublimes, at 760 mmHg | CAMEO |
| 612.78 °C (1135 °F) | sublimes | OSHA | |
| Sublimes | sublimes | NIOSH | |
| Melting point | 612.78 °C (1135 °F) | sublimes | NIOSH |
| Density | 5.73 g/cm³ | metal | NIOSH |
| 5.778 g/cm³ | at 25 °C | HSDB | |
| 5.727 g/cm³ | at 25 °C | CAMEO | |
| Solubility | Insol in caustic and nonoxidizing acids | HSDB | |
| Insoluble in water | HSDB | ||
| Insoluble | NIOSH | ||
| Vapor pressure | 0 mmHg | approx | NIOSH |
| Autoignition temperature | 180 °C (356 °F) | ICSC | |
| Lower explosive limit (LEL) | SLIGHTLY EXPLOSIVE IN THE FORM OF DUST WHEN EXPOSED TO FLAME. | HSDB | |
| Metal: Noncombustible Solid in bulk form, but a slight explosion hazard in the form of dust when exposed to flame. | NIOSH | ||
| Critical temperature and pressure | 1400 °C (2551.7 °F) | HSDB | |
| Critical pressure: 22.3 MPa | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Arsenic
Incompatible materials
Arsine is formed when any inorganic arsenic bearing material is brought in contact with zinc and sulfuric acid.
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
ARSENIC reacts incandescently with bromine trifluoride, even at 10 °C [Mellor 2:113 1946-47]. Causes bromoazide to explode upon contact. Ignites if ground up together with solid potassium permanganate [Mellor 12:322 1946-47]. Is oxidized by sodium peroxide with incandescence [Mellor 2:490-93 1946-47]. A combination of finely divided arsenic with finely divided bromates (also chlorates and iodates) of barium, calcium, magnesium, potassium, sodium, or zinc can explode by heat, percussion, and friction [Mellor 2:310 1946-47]. Bromine pentafluoride reacts readily in the cold with arsenic. Ignition usually occurs. Reacts vigorously with fluorine at ordinary temperatures [Mellor 9:34 1946-47].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Arsenic in the storage compatibility matrix →