Formic acid

Formic acid

Names
Preferred IUPAC name Formic acid
Systematic IUPAC name Methanoic acid
Other names Aminic acid; Formylic acid; Hydrogen carboxylic acid; Hydroxymethanone; Hydroxy(oxo)methane; Metacarbonoic acid; Oxocarbinic acid; Oxomethanol
Identifiers
CAS Number	64-18-6 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:30751 Y
ChEMBL	ChEMBL116736 Y
ChemSpider	278 Y
DrugBank	DB01942 Y
ECHA InfoCard	100.000.527
EC Number	200-579-1
E number	E236 (preservatives)
KEGG	C00058 Y
PubChem	284
RTECS number	LQ4900000
UNII	0YIW783RG1 Y
InChI InChI=1S/HCOOH/c2-1-3/h1H,(H,2,3) N Key: BDAGIHXWWSANSR-UHFFFAOYSA-N Y InChI=1/HCOOH/c2-1-3/h1H,(H,2,3) Key: BDAGIHXWWSANSR-UHFFFAOYAT
SMILES O=CO
Properties
Chemical formula	CH2O2
Molar mass	46.03 g·mol−1
Appearance	Colorless fuming liquid
Odor	Pungent, penetrating
Density	1.220 g/mL
Melting point	8.4 °C (47.1 °F; 281.5 K)
Boiling point	100.8 °C (213.4 °F; 373.9 K)
Solubility in water	Miscible
Solubility	Miscible with ether, acetone, ethyl acetate, glycerol, methanol, ethanol Partially soluble in benzene, toluene, xylenes
log P	−0.54
Vapor pressure	35 mmHg (20 °C)
Acidity (pKa)	3.77
Magnetic susceptibility (χ)	-19.90·10−6 cm3/mol
Refractive index (nD)	1.3714 (20 °C)
Viscosity	1.57 cP at 268 °C
Structure
Molecular shape
Dipole moment	1.41 D (gas)
Thermochemistry
Std molar entropy (So298)	131.8 J/mol K
Std enthalpy of formation (ΔfHo298)	−425.0 kJ/mol
Std enthalpy of combustion (ΔcHo298)	−254.6 kJ/mol
Pharmacology
ATCvet code	QP53AG01 (WHO)
Hazards
Main hazards	Corrosive; irritant; sensitizer
Safety data sheet	See: data page JT Baker
R-phrases	R10 R35
S-phrases	(S1/2) S23 S26 S45
NFPA 704	2 3 1
Flash point	69 °C (156 °F; 342 K)
Autoignition temperature	601 °C (1,114 °F; 874 K)
Explosive limits	14–34% 18%–57% (90% solution)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	700 mg/kg (mouse, oral), 1100 mg/kg (rat, oral), 4000 mg/kg (dog, oral)
LC50 (median concentration)	7853 ppm (rat, 15 min) 3246 ppm (mouse, 15 min)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 5 ppm (9 mg/m3)
REL (Recommended)	TWA 5 ppm (9 mg/m3)
IDLH (Immediate danger)	30 ppm
Related compounds
Related carboxylic acids	Acetic acid Propionic acid
Related compounds	Formaldehyde Methanol
Supplementary data page
Structure and properties	Refractive index (n), Dielectric constant (εr), etc.
Thermodynamic data	Phase behaviour solid–liquid–gas
Spectral data	UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Formic acid, systemically named methanoic acid, is the simplest carboxylic acid. The chemical formula is HCOOH or HCO₂H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. The word "formic" comes from the Latin word for ant, formica, referring to its early isolation by the distillation of ant bodies. Esters, salts, and the anions derived from formic acid are called formates.

Formic acid is a colorless liquid having a highly pungent, penetrating odor at room temperature. It is miscible with water and most polar organic solvents, and is somewhat soluble in hydrocarbons. In hydrocarbons and in the vapor phase, it consists of hydrogen-bonded dimers rather than individual molecules. Owing to its tendency to hydrogen-bond, gaseous formic acid does not obey the ideal gas law. Solid formic acid (two polymorphs) consists of an effectively endless network of hydrogen-bonded formic acid molecules. This relatively complicated compound also forms a low-boiling azeotrope with water (22.4%) and liquid formic acid also tends to supercool.

In nature, it is found in certain ants and in the trichomes of stinging nettle (Urtica dioica). Formic acid is a naturally occurring component of the atmosphere due primarily to forest emissions.