Formaldehyde

Athanor · official

CH₂O · 30.026 g/mol

Also called methanal, formalin, formol

Reagents Functional groups

Open in Athanor

Drawn from its SMILES with RDKit

DangerHarmful if swallowed · Causes severe skin burns and eye damage · May cause an allergic skin reaction · Fatal if inhaled · Suspected of causing genetic defects · May cause cancer

Names and identifiers

IUPAC name: formaldehyde
Synonyms: methanal, formalin, formol
+ 35 more
Formic aldehyde, Methylene oxide, Oxomethane, Oxymethylene, Methyl aldehyde, Superlysoform, Lysoform, Fannoform, Formalith, Formalina, Methaldehyde, Morbicid, Karsan, Oxomethylene, Formaline, Aldehyde formique, FYDE, Formaldehyde, gas, Formaldehyd, Aldeide formica, Formalin 40, Oplossingen, Dormol, Formalin-loesungen, Rcra waste number U122, Aldehyd mravenci, NCI-C02799, Formalinum, DTXSID7020637, NSC-298885, Formaldehyde (USP), Formaldehyde [USP], CHEBI:16842, 1HG84L3525, NSC298885
Molecular formula: CH₂O
Empirical formula: CH₂O
Molecular weight: 30.026 g/mol
Exact mass: 30.01056
CAS number: 50-00-0
PubChem CID: 712
Canonical SMILES: C=O
Isomeric SMILES: C=O
InChI: InChI=1S/CH2O/c1-2/h1H2
InChIKey: WSFSSNUMVMOOMR-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Clear, water-white, very slightly acid, gas or liquid.[6]
12 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Solids containing varying amounts of formaldehyde, probably as paraformaldehyde (polymers of formula HO(CH2O)xH where x averages about 30). A hazard to the environment. Immediate steps should be taken to limit spread to the environment. [1] CAMEO Chemicals
– Formaldehyde, solution, flammable appears as a colorless aqueous solution of formaldehyde, which is a gas at ordinary conditions. Has a pungent irritating odor. Flash point varies from 122 to 141 °F. Denser than water. The vapors are heavier than air and are highly irritating to the nose. Toxic if swallowed. Contact can cause severe injury to the skin accompanied by drying, cracking, and scaling. Used to make plastics, other chemicals, and fertilizers. Used as a preservative and a corrosion inhibitor. Rate of onset: Immediate Persistence: Hours Odor threshold: 1 ppm Source/use/other hazar [1] CAMEO Chemicals
– Formaldehyde, solutions (formalin) (corrosive) appears as a colorless liquid with a pungent irritating odor. Contains 37-50% formaldehyde by mass and varying amounts of methanol, added to prevent precipitation of formaldehyde polymers (formaldehyde exists in solution as CH2(OH)2 and its polymers HO(CH2O)xH where x averages about three). Formalin free of methanol is also shipped but must be kept warm (about 30 °C (86 °F)) to prevent polymerization. Pure formaldehyde, a gas, is not handled commercially because it tends to polymerize exothermally and may ignite. Vapor from formalin solution is fl [1] CAMEO Chemicals
– Large Crystals; CBI; Dry Powder; Gas Vapor; Wet Solid; Liquid [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS GAS WITH PUNGENT ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– COLOURLESS LIQUID WITH PUNGENT ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Colorless aqueous solution of formaldehyde with a pungent, irritating odor. Gas at ordinary conditions. [4] Occupational Safety and Health Administration (OSHA)
– Nearly colorless gas with a pungent, suffocating odor. [4] Occupational Safety and Health Administration (OSHA)
– Nearly colorless gas with a pungent, suffocating odor. [Note: Often used in an aqueous solution (see specific listing for Formalin).] [5] The National Institute for Occupational Safety and Health (NIOSH)
– Nearly colorless gas [Note: Often used in an aqueous solution]. /Pure formaldehyde/ [6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
–shown Clear, water-white, very slightly acid, gas or liquid. [6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. 2216
– Clear, colorless or nearly colorless liquid /Formaldehyde solution/ [6] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1110
Odor: Pungent, irritating odor (formaldehyde solution)[6]
Melting point: -92 °C (-134 °F, NIOSH 2024)[1]
7 values
5 of 5 sources agree on it (most common value).
Value As written Source
−92 °Cshown -134 °F (NIOSH, 2024) [1] CAMEO Chemicals
−92 °C -134 °F for anhydrous form (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−92 °C -92 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−92 °C -134 °F [4] Occupational Safety and Health Administration (OSHA)
−92 °C -134 °F [4] Occupational Safety and Health Administration (OSHA)
−92 °C -92 °C [7] PAC Chemical Database, U.S. Department of Energy
−92 °C -134 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Boiling point: -20 °C[3]
9 values
5 of 5 sources agree on it (most common value).
Value As written Source
−21 °C -6 °F at 760 mmHg (NIOSH, 2024) [1] CAMEO Chemicals
−19.5 °C -3.1 °F at 760 mmHg [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
101 °C 214 °F at 760 mmHg (NIOSH, 2024) [1] CAMEO Chemicals
−20 °Cshown -20 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
98 °C 98 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−21 °C -6 °F [4] Occupational Safety and Health Administration (OSHA)
101 °C 214 °F [4] Occupational Safety and Health Administration (OSHA)
−19.1 °C -19.1 °C @760 [mm Hg] [7] PAC Chemical Database, U.S. Department of Energy
−21 °C -6 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
2 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Density: 0.815 @ -20°C[7]
6 values
3 of 4 sources agree on it (most common value).
Value As written Source
– 0.815 at -4 °F anhydrous form (EPA, 1998) - Less dense than water [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
– 1.08 at 77 °F (NIOSH, 2024) - Denser than water [1] CAMEO Chemicals
– Relative density (water = 1): 0.8 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Relative density (water = 1): 0.8 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown 0.815 @ -20°C [7] PAC Chemical Database, U.S. Department of Energy
– 1.04(relative gas density) [5] The National Institute for Occupational Safety and Health (NIOSH)
Solubility in water: Solubility in water: miscible[3]
8 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– Miscible (NIOSH, 2024) [1] CAMEO Chemicals
– Miscible (NIOSH, 2024) [1] CAMEO Chemicals
– In water, 4.00X10+5 mg/L at 20 °C [6] Hazardous Substances Data Bank (HSDB)cites Pickrell JA et al; Environ Sci Technol 17: 753-7 (1983)
– In water, miscible at 25 °C [6] Hazardous Substances Data Bank (HSDB)cites Abatjoglou AG, Miller DJ; Aldehydes. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Jul 15, 2011.
– In water, 95 weight % at 20 °C [6] Hazardous Substances Data Bank (HSDB)cites Kohlpaintner C et al; Aldehydes, Aliphatic. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Jan 15, 2013.
– Solubility in water: very good [3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown Solubility in water: miscible [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Miscible [5] The National Institute for Occupational Safety and Health (NIOSH)
log P: log Kow = 0.35[6]
pKa: pKa = 13.27 at 25 °C[6]
Vapor pressure: 3,890 mmHg at 25 °C /100% formaldehyde/[6]
4 values
Sources disagree; from Hazardous Substances Data Bank (HSDB), the most authoritative.
Value As written Source
10 mmHg 10 mmHg at -126.4 °F for anhydrous form (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
3890 mmHgshown 3,890 mm Hg at 25 °C /100% formaldehyde/ [6] Hazardous Substances Data Bank (HSDB)cites Boublik, T., Fried, V., and Hala, E., The Vapour Pressures of Pure Substances. Second Revised Edition. Amsterdam: Elsevier, 1984., p. 44
1.5 mmHg Vapor pressure, kPa at 20 °C: 0.2 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
750 mmHg 750 [mm Hg] @-19.3 °C [7] PAC Chemical Database, U.S. Department of Energy
6 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Flash point: 85 °C (185 °F) (Closed cup) (gas)[6]
7 values
3 of 4 sources agree on it (most common value).
Value As written Source
60 °C 140 °F for 40% solution (EPA, 1998) [1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
85 °C 185 °F (NIOSH, 2024) [1] CAMEO Chemicals
85 °Cshown 185 °F (85 °C) (Closed cup) /Gas/ [6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-66
50 °C 122 °F (50 °C) (Closed cup) /Formaldehyde 37%, 15% methanol/ [6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-66
85 °C 185 °F (85 °C) (Closed cup) /Formaldehyde 37%, methanol-free [6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-66
83 °C 83 °C c.c. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
85 °C 185 °F [4] Occupational Safety and Health Administration (OSHA)
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Autoignition temperature: 430 °C[3]
3 values
2 of 3 sources agree on it (most common value).
Value As written Source
430 °C 806 °F (USCG, 1999) [1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
424 °C 795 °F (424 °C) [6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-66
430 °Cshown 430 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Viscosity: 0.1421 cP at 25 °C[6]

Value	As written	Source
–	Solids containing varying amounts of formaldehyde, probably as paraformaldehyde (polymers of formula HO(CH2O)xH where x averages about 30). A hazard to the environment. Immediate steps should be taken to limit spread to the environment.	[1] CAMEO Chemicals
–	Formaldehyde, solution, flammable appears as a colorless aqueous solution of formaldehyde, which is a gas at ordinary conditions. Has a pungent irritating odor. Flash point varies from 122 to 141 °F. Denser than water. The vapors are heavier than air and are highly irritating to the nose. Toxic if swallowed. Contact can cause severe injury to the skin accompanied by drying, cracking, and scaling. Used to make plastics, other chemicals, and fertilizers. Used as a preservative and a corrosion inhibitor. Rate of onset: Immediate Persistence: Hours Odor threshold: 1 ppm Source/use/other hazar	[1] CAMEO Chemicals
–	Formaldehyde, solutions (formalin) (corrosive) appears as a colorless liquid with a pungent irritating odor. Contains 37-50% formaldehyde by mass and varying amounts of methanol, added to prevent precipitation of formaldehyde polymers (formaldehyde exists in solution as CH2(OH)2 and its polymers HO(CH2O)xH where x averages about three). Formalin free of methanol is also shipped but must be kept warm (about 30 °C (86 °F)) to prevent polymerization. Pure formaldehyde, a gas, is not handled commercially because it tends to polymerize exothermally and may ignite. Vapor from formalin solution is fl	[1] CAMEO Chemicals
–	Large Crystals; CBI; Dry Powder; Gas Vapor; Wet Solid; Liquid	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS GAS WITH PUNGENT ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	COLOURLESS LIQUID WITH PUNGENT ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Colorless aqueous solution of formaldehyde with a pungent, irritating odor. Gas at ordinary conditions.	[4] Occupational Safety and Health Administration (OSHA)
–	Nearly colorless gas with a pungent, suffocating odor.	[4] Occupational Safety and Health Administration (OSHA)
–	Nearly colorless gas with a pungent, suffocating odor. [Note: Often used in an aqueous solution (see specific listing for Formalin).]	[5] The National Institute for Occupational Safety and Health (NIOSH)
–	Nearly colorless gas [Note: Often used in an aqueous solution]. /Pure formaldehyde/	[6] Hazardous Substances Data Bank (HSDB)cites NIOSH. NIOSH Pocket Guide to Chemical Hazards. Department of Health & Human Services, Centers for Disease Control & Prevention. National Institute for Occupational Safety & Health. DHHS (NIOSH) Publication No. 2010-168 (2010). Available from: https://www.cdc.gov/niosh/npg
–shown	Clear, water-white, very slightly acid, gas or liquid.	[6] Hazardous Substances Data Bank (HSDB)cites Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 12th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2012., p. 2216
–	Clear, colorless or nearly colorless liquid /Formaldehyde solution/	[6] Hazardous Substances Data Bank (HSDB)cites Osol, A. (ed.). Remington's Pharmaceutical Sciences. 16th ed. Easton, Pennsylvania: Mack Publishing Co., 1980., p. 1110

Value	As written	Source
−92 °Cshown	-134 °F (NIOSH, 2024)	[1] CAMEO Chemicals
−92 °C	-134 °F for anhydrous form (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
−92 °C	-92 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−92 °C	-134 °F	[4] Occupational Safety and Health Administration (OSHA)
−92 °C	-134 °F	[4] Occupational Safety and Health Administration (OSHA)
−92 °C	-92 °C	[7] PAC Chemical Database, U.S. Department of Energy
−92 °C	-134 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
−21 °C	-6 °F at 760 mmHg (NIOSH, 2024)	[1] CAMEO Chemicals
−19.5 °C	-3.1 °F at 760 mmHg	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
101 °C	214 °F at 760 mmHg (NIOSH, 2024)	[1] CAMEO Chemicals
−20 °Cshown	-20 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
98 °C	98 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−21 °C	-6 °F	[4] Occupational Safety and Health Administration (OSHA)
101 °C	214 °F	[4] Occupational Safety and Health Administration (OSHA)
−19.1 °C	-19.1 °C @760 [mm Hg]	[7] PAC Chemical Database, U.S. Department of Energy
−21 °C	-6 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	0.815 at -4 °F anhydrous form (EPA, 1998) - Less dense than water	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
–	1.08 at 77 °F (NIOSH, 2024) - Denser than water	[1] CAMEO Chemicals
–	Relative density (water = 1): 0.8	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Relative density (water = 1): 0.8	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown	0.815 @ -20°C	[7] PAC Chemical Database, U.S. Department of Energy
–	1.04(relative gas density)	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	Miscible (NIOSH, 2024)	[1] CAMEO Chemicals
–	Miscible (NIOSH, 2024)	[1] CAMEO Chemicals
–	In water, 4.00X10+5 mg/L at 20 °C	[6] Hazardous Substances Data Bank (HSDB)cites Pickrell JA et al; Environ Sci Technol 17: 753-7 (1983)
–	In water, miscible at 25 °C	[6] Hazardous Substances Data Bank (HSDB)cites Abatjoglou AG, Miller DJ; Aldehydes. Kirk-Othmer Encyclopedia of Chemical Technology. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Jul 15, 2011.
–	In water, 95 weight % at 20 °C	[6] Hazardous Substances Data Bank (HSDB)cites Kohlpaintner C et al; Aldehydes, Aliphatic. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2014). New York, NY: John Wiley & Sons. Online Posting Date: Jan 15, 2013.
–	Solubility in water: very good	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–shown	Solubility in water: miscible	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Miscible	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
10 mmHg	10 mmHg at -126.4 °F for anhydrous form (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
3890 mmHgshown	3,890 mm Hg at 25 °C /100% formaldehyde/	[6] Hazardous Substances Data Bank (HSDB)cites Boublik, T., Fried, V., and Hala, E., The Vapour Pressures of Pure Substances. Second Revised Edition. Amsterdam: Elsevier, 1984., p. 44
1.5 mmHg	Vapor pressure, kPa at 20 °C: 0.2	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
750 mmHg	750 [mm Hg] @-19.3 °C	[7] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
60 °C	140 °F for 40% solution (EPA, 1998)	[1] CAMEO Chemicalscites U.S. Environmental Protection Agency. 1998. Extremely Hazardous Substances (EHS) Chemical Profiles and Emergency First Aid Guides. Washington, D.C.: U.S. Government Printing Office.
85 °C	185 °F (NIOSH, 2024)	[1] CAMEO Chemicals
85 °Cshown	185 °F (85 °C) (Closed cup) /Gas/	[6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-66
50 °C	122 °F (50 °C) (Closed cup) /Formaldehyde 37%, 15% methanol/	[6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-66
85 °C	185 °F (85 °C) (Closed cup) /Formaldehyde 37%, methanol-free	[6] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-66
83 °C	83 °C c.c.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
85 °C	185 °F	[4] Occupational Safety and Health Administration (OSHA)

Value	As written	Source
430 °C	806 °F (USCG, 1999)	[1] CAMEO Chemicalscites U.S. Coast Guard. 1999. Chemical Hazard Response Information System (CHRIS) - Hazardous Chemical Data. Commandant Instruction 16465.12C. Washington, D.C.: U.S. Government Printing Office.
424 °C	795 °F (424 °C)	[6] Hazardous Substances Data Bank (HSDB)cites Fire Protection Guide to Hazardous Materials. 13 ed. Quincy, MA: National Fire Protection Association, 2002., p. 325-66
430 °Cshown	430 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 2
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 0
H-bond acceptors: 1
Rotatable bonds: 0
TPSA (Å²): 17.1
Formal charge: 0
XLogP3: 1.2 PubChem
Complexity: 2 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C2v of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C40.00%
H6.71%
O53.28%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: -0.18 Crippen (Wildman and Crippen 1999)
log S (water solubility): 0.09 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 4.04 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 30.03
log P ≤ 5 (Crippen): -0.18
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 1

Passes all four rules.

¹³C NMR shifts, predicted

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [8].

Corrosive
Acute toxicity
Health hazard

NFPA 704[6]

H302Harmful if swallowed
H314Causes severe skin burns and eye damage
H317May cause an allergic skin reaction
H330Fatal if inhaled
H341Suspected of causing genetic defects
H350May cause cancer

Precautionary statements: P203, P260, P261, P264, P270, P271, P272, P280, P284, P301+P317, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P316, P318, P320, P321, P330, P333+P317, P362+P364, P363, P403+P233, P405, P501

View all classifications (4)

[8] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH302, H314, H317, H330, H341, H350
[9] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for < 0.1% (3 of 6451) of reports.
[9] European Chemicals Agency (ECHA) · 6,451 reports · DangerH301, H311, H314, H317, H318, H330, H331, H341, H350, H351
[6] Hazardous Substances Data Bank (HSDB) · DangerH227, H301, H311, H314, H317, H318, H331, H341, H350, H370, H402

Exposure limits

PEL-TWA (8-Hour Time Weighted Average): 0.75 ppm [0.5 ppm Action Level][4]
PEL-STEL (Short Term Exposure Limit): 2 ppm[4]
PEL: [1910.1048] TWA 0.75 ppm ST 2 ppm[5]
REL-TWA (Time Weighted Average): 0.016 ppm[4]
REL-C (Ceiling): 0.1 ppm [15 minutes][4]
REL: Ca TWA 0.016 ppm C 0.1 ppm [15-minute] See Appendix A[5]

First aid

Excerpt from NIOSH Pocket Guide for Formaldehyde: Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Breathing: Respiratory support - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible. (NIOSH, 2024)[1]
Signs and Symptoms of Acute Formaldehyde Exposure: Acute exposure to formaldehyde may result in irritation or burns to the skin, eyes, and mucous membranes; lacrimation (tearing); nausea; vomiting (may be bloody); abdominal pain; and diarrhea. Difficulty in breathing, cough, pneumonia, and pulmonary edema may occur. Sensitized people may experience asthmatic reactions, even when exposed briefly. Hypotension (low blood pressure) and hypothermia (reduced body temperature) may precede cardiovascular collapse. Lethargy, dizziness, convulsions, and coma may be noted. Nephritis (inflammation of the[1]
Excerpt from NIOSH Pocket Guide for Formalin (as formaldehyde): Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately. Skin: Water flush promptly - If this chemical contacts the skin, flush the contaminated skin with water promptly. If this chemical penetrates the clothing, immediately remove the clothing and flush the skin with water promptly.[1]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[10]

Storage

Fireproof. Cool. Separated from incompatible materials. See Chemical Dangers.[3]
Cool. Well closed. Keep in a well-ventilated room. Separated from acids, strong oxidants and food and feedstuffs. See Chemical Dangers. Store in an area without drain or sewer access.[3]
... Minimum storage temperature to prevent polymerization range from 28 °C (83 °F) for 37% formaldehyde containing 0.05% methyl alcohol to -2 °C (29 °F) for formaldehyde containing 15% methyl alcohol.[6]
Formalin is ... Supplied unstabilized or methanol-stabilized. The latter may be stored at room temp without precipitation of solid formaldehyde polymers because it contains 5-10% of methyl alcohol. The uninhibited type must be maintained at a temp of at least 32 °C to prevent the separation of solid formaldehyde polymers.[6]

Incompatibilities

(Amines) exothermic reaction, (AZO cmpd) exothermic reaction giving off nitrogen gas, (caustics) heat generation and violent polymerization, (dithiocarbamates) formation of flammable gasses and toxic fumes, formation of carbon disulfide may result, (alkali and alkaline earth metals) heat generation and formation of flammable hydrogen gas, (nitrides) heat generation, formation of flammable ammonia gas and violent polymerization, (nitro compd) heat generation, (unsaturated aliphatics and sulfides) heat generation, (organic peroxides) violent reaction, (oxidizing agents) heat generation, fire,…[6]
Interaction of nitromethane & formaldehyde in presence of alkali gives ... 2-nitroethanol ... (and) di- & tri-condensation products. After removal of 2-nitroethanol by vacuum distillation, the residue must be cooled before admitting air into the system to prevent flash explosion or violent fume-off. (nitromethane: Formaldehyde)[6]
Formaldehyde ... React violently with 90% performic acid ... (peroxyformic acid: Organic materials)[6]
Formaldehyde and a number of carbonyl cmpd bearing electronegative substituents in the alpha position add to isocyanic acid at temp of -70 deg to 0 °C to form alpha-hydroxy isocyanates. At higher temp, these isocyanates polymerize and sometimes do so with explosive violence.[6]

Safety data sheets on the supplier’s page: MuseChem, abcr GmbH, Thermo Fisher Scientific.

Always read the supplier’s safety data sheet before working with it.

Spectra

Experimental spectra held by these sources; each link opens the source's own record.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Occupational Safety and Health Administration (OSHA) · Public domain (US DOL) · via PubChem · retrieved 2026-10-14
[5]The National Institute for Occupational Safety and Health (NIOSH) · Public domain (US CDC) · via PubChem · retrieved 2026-10-14
[6]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[7]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[8]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[9]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[10]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[11]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[12]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[13]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.