Formaldehyde

Formaldehyde
Structural formula of formaldehyde (with hydrogens)	Spacefill model of formaldehyde
	Ball and stick model of formaldehyde
Names
	Preferred IUPAC name Formaldehyde
	Systematic IUPAC name Methanal
	Other names Methyl aldehyde; Methylene glycol (diol forms in aqueous solution); Methylene oxide; Formalin (aqueous solution); Formol; Carbonyl hydride; Methanone; Oxomethane; Formic aldehyde;
Identifiers
CAS Number	50-00-0 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	1209228
ChEBI	CHEBI:16842 ;
ChEMBL	ChEMBL1255 ;
ChemSpider	692 ;
DrugBank	DB03843 ;
ECHA InfoCard	100.000.002
EC Number	200-001-8;
E number	E240 (preservatives)
Gmelin Reference	445
IUPHAR/BPS	4196;
KEGG	D00017 ;
MeSH	Formaldehyde
PubChem CID	712;
RTECS number	LP8925000;
UNII	1HG84L3525 ;
UN number	2209
CompTox Dashboard (EPA)	DTXSID7020637 ;
	InChI InChI=1S/CH2O/c1-2/h1H2 Key: WSFSSNUMVMOOMR-UHFFFAOYSA-N ; InChI=1/CH2O/c1-2/h1H2 Key: WSFSSNUMVMOOMR-UHFFFAOYAT;
	SMILES C=O;
Properties
Chemical formula	CH2O
Molar mass	30.026 g·mol−1
Appearance	Colorless gas
Density	0.8153 g/cm3 (−20 °C) (liquid)
Melting point	−92 °C (−134 °F; 181 K)
Boiling point	−19 °C (−2 °F; 254 K)
Solubility in water	400 g/L
log P	0.350
Vapor pressure	> 1 atm
Acidity (pKa)	13.27 (hydrate)
Magnetic susceptibility (χ)	−18.6·10−6 cm3/mol
Dipole moment	2.330 D
Structure
Point group	C2v
Molecular shape	Trigonal planar
Thermochemistry
Heat capacity (C)	35.387 J·mol−1·K−1
Std molar; entropy (S⦵298)	218.760 J·mol−1·K−1
Std enthalpy of; formation (ΔfH⦵298)	−108.700 kJ·mol−1
Gibbs free energy (ΔfG⦵)	−102.667 kJ·mol−1
Std enthalpy of; combustion (ΔcH⦵298)	571 kJ·mol−1
Pharmacology
ATCvet code	QP53AX19 (WHO)
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301+H311+H331, H314, H317, H335, H341, H350, H370
Precautionary statements	P201, P280, P303+P361+P353, P304+P340+P310, P305+P351+P338, P308+P310
NFPA 704 (fire diamond)	4 4 0 COR
Flash point	64 °C (147 °F; 337 K)
Autoignition; temperature	430 °C (806 °F; 703 K)
Explosive limits	7–73%
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	100 mg/kg (oral, rat)
LC50 (median concentration)	333 ppm (mouse, 2 h); 815 ppm (rat, 30 min)
LCLo (lowest published)	333 ppm (cat, 2 h)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.75 ppm ST 2 ppm (as formaldehyde and formalin)
REL (Recommended)	Ca TWA 0.016 ppm C 0.1 ppm [15-minute]
IDLH (Immediate danger)	Ca [20 ppm]
Safety data sheet (SDS)	MSDS(Archived)
Related compounds
Related aldehydes	Acetaldehyde;
Related compounds	Methanol; Formic acid; Methylene imine; Thioformaldehyde;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Formaldehyde (/fɔːrˈmældɪhaɪd/ ^ⓘ for-MAL-di-hide, US also /fər-/ ^ⓘ fər-) (systematic name methanal) is a pungent colorless gas mainly used in the production of industrial resins, such as for particle board, coatings, plastics, pulp, paper, synthetic fibers, and textiles. A ~5% solution in water of formaldehyde is used as a disinfectant and fumigant in industrial, agricultural, and healthcare settings, and a ~37% solution is used to preserve tissue samples in labs. In 2024, the global production of formaldehyde was estimated at 26 million tons per year, and is a precursor to many other materials and chemical compounds.

It is an organic compound with the chemical formula CH₂O and structure H₂C=O. The gas spontaneously polymerizes into paraformaldehyde. It is stored as a ~37% aqueous solution known as formalin, which consists mainly of the hydrate CH₂(OH)₂. It is the simplest of the aldehydes (R−CHO).

Formaldehyde also occurs naturally. It is derived from the degradation of serine, dimethylglycine, and lipids. Demethylases act by converting N-methyl groups to formaldehyde.

Formaldehyde is classified as a group 1 carcinogen and can cause respiratory and skin irritation upon exposure.