Provenance

Reference data from EU CLP Annex VI and published regulations — verify against your supplier's SDS before use.

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Substance profile

Formic acid

Formic acid is a colorless fuming liquid with a pungent, penetrating odor.

CAS 64-18-6 CH2O2 46.025 g/mol Danger

Formic acid Safety Data Sheet →

01 · Identification

What Formic acid is

Formic acid is a colorless fuming liquid with a pungent, penetrating odor. Its molecular formula is CH2O2 and its molecular weight is 46.025 g/mol. It boils at 101 °C, melts at 8.3 °C, is miscible with water.

Under the GHS it carries the signal word Danger. It is classed as corrosives.

CAS number64-18-6
EC number200-579-1
Index number607-001-00-0
Molecular formulaCH2O2
Molecular weight46.025 g/mol
Chemical class Corrosives

Other names for Formic acid

  • methanoic acid
  • HCOOH
  • Add-F
  • Ameisensaure
  • Aminic Acid
  • Bilorin
  • Collo-Bueglatt
  • Collo-Didax
  • Formic Acid (85-95% In Aqueous Solution)
  • Formira
  • Formisoton
  • Formylic Acid
  • Hydrogen Carboxylic Acid
  • Methanoic Acid Monomer
  • formic acid … %

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.

Signal wordDanger
Hazard statements assigned to Formic acid
CodeHazard statement
H226 Flammable liquid and vapour.
H290 May be corrosive to metals.
H331 Toxic if inhaled.
H302 Harmful if swallowed.
H314 Causes severe skin burns and eye damage.
H318 Causes serious eye damage.

Supplemental EU statements: EUH071

Precautionary statements: P210, P233, P241, P242, P260, P270, P271, P280, P301, P304, P305, P310, P312, P330, P331, P338, P403

03 · Physical and chemical properties

Formic 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 101 °C (213.8 °F) HSDB
106.67 °C (224 °F) NIOSH
100.72 °C (213.3 °F) at 760 mmHg CAMEO
Melting point 8.3 °C (46.9 °F) HSDB
-6.67 °C (20 °F) NIOSH
8.39 °C (47.1 °F) CAMEO
Density 1.22 g/cm³ NIOSH
1.22 g/cm³ at 20 °C HSDB
1.2174 g/cm³ at 20 °C HSDB
Solubility Miscible with ether, acetone, ethyl acetate, methanol, ethanol; partially soluble in benzene, toluene, xylenes HSDB
Dissolves to the extent of about 10% in benzene, toluene, and xylenes, and to a lesser extent in aliphatic hydrocarbons. HSDB
Miscible with water HSDB
Vapor pressure 35 mmHg NIOSH
35 mmHg at 20 °C CAMEO
42.59 mmHg at 25 °C, Extrapolated HSDB
Flash point 68.89 °C (156 °F) HSDB
58.89 °C (138 °F) HSDB
50 °C (122 °F) NIOSH
Autoignition temperature 540 °C (1004 °F) HSDB
601.11 °C (1114 °F) CAMEO
520 °C (968 °F) ICSC
Lower explosive limit (LEL) 18 % by volume HSDB
Upper explosive limit (UEL) 57 % by volume HSDB
Vapor density 1.59 (air = 1) HSDB
1.6 (air = 1) CAMEO
Odor threshold Water: 1700 mg/L; air 49 uL/L; Odor safety class E. E= less than 10% of attentive persons can detect TLV concentration in the air. HSDB
Detection threshold: 4.50x10+2 mg/L (liq) and 4.50x10-1 mg/L (gas) Purity not specified HSDB
Detection threshold: 6.25x10-1 ppm, 6.25x10-2 ppm and 8.30x10+1 ppm Medium water; purity not specified HSDB
Critical temperature and pressure 314.85 °C (598.7 °F) HSDB
Corrosivity Corrosive to metals HSDB

Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.

04 · Handling and storage

Storing and handling Formic acid

Storage conditions

Store in a dry, well-ventilated place. Separate from oxidizing materials and alkaline substances.

Source: Hazardous Substances Data Bank (HSDB)

Incompatible materials

/Aluminium/ ... reduces the acid (itself a reducant) with incandescence.

Source: Hazardous Substances Data Bank (HSDB)

Reactivity

FORMIC ACID reacts exothmerically with all bases, both organic (for example, the amines) and inorganic. Reacts with active metals to form gaseous hydrogen and a metal salt. Reacts with cyanide salts to generate gaseous hydrogen cyanide. Reacts with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides to generate flammable or toxic gases. Reacts with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat. Reacts with carbonates and bicarbonates to generate carbon dioxide but still heat. Can be oxidized by strong oxidizing agents and reduced by strong reducing agents. These reactions generate heat. May initiate polymerization reactions or catalyze other chemical reactions. A mixture with furfuryl alcohol exploded [Chem. Eng. News 18:72(1940)].

Source: CAMEO Chemicals

Planning storage for a mix of chemicals? Check Formic acid in the storage compatibility matrix →

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