Substance profile
Hydrofluoric acid
Hydrofluoric acid is a colorless gas, fumes in air with a strong, irritating odor.
01 · Identification
What Hydrofluoric acid is
Hydrofluoric acid is a colorless gas, fumes in air with a strong, irritating odor. Its molecular formula is FH and its molecular weight is 20.006 g/mol. It boils at 19.4 °C, melts at -83.6 °C, is miscible with water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
Other names for Hydrofluoric acid
- hydrogen fluoride
- HF
- Anhydrous Hydrofluoric Acid
- Anhydrous Hydrogen Fluoride
- Aqueous Hydrogen Fluoride (I.E., Hydrofluoric Acid)
- Fluorhydric Acid
- Fluoric Acid
- Fluorine Hydride (Fh)
- Fluorine Monohydride
- Hf-A
- Hydrofluoric Acid Gas
- Hydrofluoric Acid, Anhydrous
- Hydrogen Fluoride (Anhydrous)
- Hydrogen Fluoride (Hf)
- Alsurf 45
- Antisal 2B
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 |
|---|---|
| H310 | Fatal in contact with skin. |
| H330 | Fatal if inhaled. |
| H300 | Fatal if swallowed. |
| H314 | Causes severe skin burns and eye damage. |
Precautionary statements: P260, P270, P271, P280, P301, P302, P304, P310, P330, P331, P352
03 · Physical and chemical properties
Hydrofluoric acid 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 | 19.44 °C (67 °F) | NIOSH | |
| 66.67 °C (152 °F) | at 760 mmHg | CAMEO | |
| 19.5 °C (67.1 °F) | at 760 mmHg | CAMEO | |
| Melting point | -83.57 °C (-118.4 °F) | HSDB | |
| -83.33 °C (-118 °F) | NIOSH | ||
| -69 °C (-92.2 °F) | CAMEO | ||
| Density | 1.23 g/cm³ | CAMEO | |
| 0.991 g/cm³ | at 19.5 °C | CAMEO | |
| 1 g/cm³ | at 19.44 °C | NIOSH | |
| Solubility | Miscible with water | HSDB | |
| Very soluble in water | HSDB | ||
| Very soluble in alcohol, slightly soluble in ether, soluble in many organic solvents | HSDB | ||
| Vapor pressure | 783 mmHg | NIOSH | |
| 917 mmHg | at 25 °C | HSDB | |
| 150 mmHg | at 25 °C, partial pressure for 70% solution | CAMEO | |
| Flash point | Not Flammable (EPA, 1998) | CAMEO | |
| Autoignition temperature | Not flammable (USCG, 1999) | CAMEO | |
| Lower explosive limit (LEL) | Nonflammable Gas | NIOSH | |
| Non-Flammable (EPA, 1998) | CAMEO | ||
| Upper explosive limit (UEL) | Non-Flammable (EPA, 1998) | CAMEO | |
| Vapor density | 0.7 (air = 1) | CAMEO | |
| 1.86 (air = 1) | at 25 °C | CAMEO | |
| Odor threshold | Odor ... is detectable in air @ 0.5 to 3 ppm. | HSDB | |
| Odor low 0.0333 mg/cu m; Odor high 0.1333 mg/cu m; Irritating concn 4.17 mg/cu m. | HSDB | ||
| Odor Threshold Low: 0.04 [ppm] | Haz-Map | ||
| Critical temperature and pressure | 188 °C (370.4 °F) | HSDB | |
| Corrosivity | Corrosive, dissolves silica, silicic acid, glass | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
04 · Handling and storage
Storing and handling Hydrofluoric acid
Storage conditions
Hydrogen fluoride should be stored in cool, dry, well ventilated areas out of the direct rays of the sun.
Source: Hazardous Substances Data Bank (HSDB)
Incompatible materials
Metals, water or steam. [Note: Corrosive to metals. Will attack glass and concrete].
Source: Hazardous Substances Data Bank (HSDB)
Reactivity
Mixing in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: acetic anhydride, 2-aminoethanol, chlorosulfonic acid, aqueous ammonia (48.7%), ethylenediamine, ethyleneimine, oleum, aqueous sulfuric acid (48.7%), aqueous sodium hydroxide (48.7%), propylene oxide, vinyl acetate [NFPA 1991].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Hydrofluoric acid in the storage compatibility matrix →
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