Methane

Athanor · official

CH₄ · 16.043 g/mol

Also called natural gas, marsh gas, CH4

Reagents

Open in Athanor

Drawn from its SMILES with RDKit

DangerExtremely flammable gas

Names and identifiers

IUPAC name: methane
Synonyms: natural gas, marsh gas, CH4
+ 34 more
Marsh gas, Methyl hydride, Fire Damp, Biogas, R 50 (refrigerant), metano, tetrahydridocarbon, HSDB 167, Methane in gaseus state, UN1972, BRN 1718732, OP0UW79H66, UN1971, DTXSID8025545, UNII-OP0UW79H66, CHEBI:16183, R 50, Methane-12C, RefChem:6654, methane;tetrahydridocarbon, AC1L18XA, CHEMBL17564, DTXCID705545, CTK2H7747, AC1Q2825, AKOS005166816, C01438, 0CB689EE-132E-4559-A597-C79A40192203, 200-812-7, 02329_FLUKA, 295477_ALDRICH, 3B4-2254, 463035_ALDRICH, 490210_ALDRICH
Molecular formula: CH₄
Empirical formula: CH₄
Molecular weight: 16.043 g/mol
Exact mass: 16.03130
CAS number: 74-82-8
PubChem CID: 297
Canonical SMILES: C
Isomeric SMILES: C
InChI: InChI=1S/CH4/h1H4
InChIKey: VNWKTOKETHGBQD-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Methane, refrigerated liquid (cryogenic liquid) is a colorless odorless liquid. Flammable. Water insoluble.[1]
6 values
From CAMEO Chemicals, the most authoritative source here.
Value As written Source
– Methane is a colorless odorless gas. It is also known as marsh gas or methyl hydride. It is easily ignited. The vapors are lighter than air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. It is used in making other chemicals and as a constituent of the fuel, natural gas. [1] CAMEO Chemicals
– Methane is a colorless odorless gas. It is also known as marsh gas or methyl hydride. It is easily ignited. The vapors are lighter than air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. It is used in making other chemicals and as a constituent of the fuel, natural gas. [1] CAMEO Chemicals
–shown Methane, refrigerated liquid (cryogenic liquid) is a colorless odorless liquid. Flammable. Water insoluble. [1] CAMEO Chemicals
– Natural gas, [compressed] appears as a flammable gaseous mixture of straight chain hydrocarbons, predominately compressed methane. [1] CAMEO Chemicals
– Liquid; CBI; Gas Vapor [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS ODOURLESS COMPRESSED OR LIQUEFIED GAS. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Odor: Weak odor[4]
Melting point: -182.47 °C[5]
4 values
3 of 3 sources agree on it (most common value).
Value As written Source
−182 °C -296 °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.
−182.5 °C -296.5 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−183 °C -183 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−182.5 °Cshown -182.47 °C [5] PAC Chemical Database, U.S. Department of Energy
Boiling point: -161.48 °C @760 [mmHg][5]
4 values
3 of 3 sources agree on it (most common value).
Value As written Source
−161 °C -258 °F at 760 mmHg (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.
−161.5 °C -258.7 °F at 760 mmHg (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−161 °C -161 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−161.5 °Cshown -161.48 °C @760 [mm Hg] [5] PAC Chemical Database, U.S. Department of Energy
Density: 0.4228 @ -162°C[5]
3 values
2 of 2 sources agree on it (most common value).
Value As written Source
– 0.415 to 0.45 at -259.6 °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.
– 0.422 at -256 °F (USCG, 1999) - Less dense than water [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.
–shown 0.4228 @ -162°C [5] PAC Chemical Database, U.S. Department of Energy
Solubility in water: Solubility in water, ml/100ml at 20 °C: 3.3[3]
4 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– 3.5 mL/100 mL at 63 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
– In water, 22 mg/L at 25 °C [4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 8
– 0.91 mL in 1 g ether at 20 °C; 0.60 mL in 1 g ethyl alcohol at 20 °C [4] Hazardous Substances Data Bank (HSDB)cites Patty, F. (ed.). Industrial Hygiene and Toxicology: Volume II: Toxicology. 2nd ed. New York: Interscience Publishers, 1963., p. 1197
–shown Solubility in water, ml/100ml at 20 °C: 3.3 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
log P: 1.09[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
– log Kow = 1.09 [4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 3
–shown 1.09 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Vapor pressure: 750 [mmHg] @-161.69999999999999 °C[5]
4 values
2 of 3 sources agree on it (most common value).
Value As written Source
258574 mmHg 258574 mmHg at 100 °F [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
760 mmHg 760 mmHg at -258.7 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
466000 mmHg 4.66X10+5 mm Hg at 25 °C [4] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
750 mmHgshown 750 [mm Hg] @-161.69999999999999 °C [5] PAC Chemical Database, U.S. Department of Energy
Flash point: -188 °C (-306 °F) - closed cup[4]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
−188 °C -306 °F (NTP, 1992) [1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−188 °Cshown -188 °C (-306 °F) - closed cup [4] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich Material Safety Data Sheet for methane. Product number 295477. Version 3.3. (December 5, 2012). Available from, as of November 6, 2013. https://www.sigmaaldrich.com/catalog/product/aldrich/295477?lang=en&region=US
Autoignition temperature: 537 °C[3]
4 values
3 of 3 sources agree on it (most common value).
Value As written Source
537 °C 999 °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.
540 °C 1004 °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.
537 °C 999 °F (537 °C) [4] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-106
537 °Cshown 537 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	Methane is a colorless odorless gas. It is also known as marsh gas or methyl hydride. It is easily ignited. The vapors are lighter than air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. It is used in making other chemicals and as a constituent of the fuel, natural gas.	[1] CAMEO Chemicals
–	Methane is a colorless odorless gas. It is also known as marsh gas or methyl hydride. It is easily ignited. The vapors are lighter than air. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. It is used in making other chemicals and as a constituent of the fuel, natural gas.	[1] CAMEO Chemicals
–shown	Methane, refrigerated liquid (cryogenic liquid) is a colorless odorless liquid. Flammable. Water insoluble.	[1] CAMEO Chemicals
–	Natural gas, [compressed] appears as a flammable gaseous mixture of straight chain hydrocarbons, predominately compressed methane.	[1] CAMEO Chemicals
–	Liquid; CBI; Gas Vapor	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS ODOURLESS COMPRESSED OR LIQUEFIED GAS.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
−182 °C	-296 °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.
−182.5 °C	-296.5 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−183 °C	-183 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−182.5 °Cshown	-182.47 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
−161 °C	-258 °F at 760 mmHg (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.
−161.5 °C	-258.7 °F at 760 mmHg (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−161 °C	-161 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−161.5 °Cshown	-161.48 °C @760 [mm Hg]	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	0.415 to 0.45 at -259.6 °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.
–	0.422 at -256 °F (USCG, 1999) - Less dense than water	[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.
–shown	0.4228 @ -162°C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–	3.5 mL/100 mL at 63 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
–	In water, 22 mg/L at 25 °C	[4] Hazardous Substances Data Bank (HSDB)cites Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 8
–	0.91 mL in 1 g ether at 20 °C; 0.60 mL in 1 g ethyl alcohol at 20 °C	[4] Hazardous Substances Data Bank (HSDB)cites Patty, F. (ed.). Industrial Hygiene and Toxicology: Volume II: Toxicology. 2nd ed. New York: Interscience Publishers, 1963., p. 1197
–shown	Solubility in water, ml/100ml at 20 °C: 3.3	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
–	log Kow = 1.09	[4] Hazardous Substances Data Bank (HSDB)cites Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 3
–shown	1.09	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
258574 mmHg	258574 mmHg at 100 °F	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
760 mmHg	760 mmHg at -258.7 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
466000 mmHg	4.66X10+5 mm Hg at 25 °C	[4] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
750 mmHgshown	750 [mm Hg] @-161.69999999999999 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
−188 °C	-306 °F (NTP, 1992)	[1] CAMEO Chemicalscites National Toxicology Program, Institute of Environmental Health Sciences, National Institutes of Health (NTP). 1992. National Toxicology Program Chemical Repository Database. Research Triangle Park, North Carolina.
−188 °Cshown	-188 °C (-306 °F) - closed cup	[4] Hazardous Substances Data Bank (HSDB)cites Sigma-Aldrich Material Safety Data Sheet for methane. Product number 295477. Version 3.3. (December 5, 2012). Available from, as of November 6, 2013. https://www.sigmaaldrich.com/catalog/product/aldrich/295477?lang=en&region=US

Value	As written	Source
537 °C	999 °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.
540 °C	1004 °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.
537 °C	999 °F (537 °C)	[4] Hazardous Substances Data Bank (HSDB)cites National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 49-106
537 °Cshown	537 °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: 1
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 1
H-bond donors: 0
H-bond acceptors: 0
Rotatable bonds: 0
TPSA (Å²): 0
Formal charge: 0
XLogP3: 0.6 PubChem
Complexity: 0 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: Td of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

C74.87%
H25.13%

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: 0.64 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.34 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 7.33 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 16.04
log P ≤ 5 (Crippen): 0.64
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 0

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 [6].

Flammable
Compressed gas

NFPA 704[4]

H220Extremely flammable gas

Precautionary statements: P203, P210, P222, P280, P377, P381, P403

View all classifications (2)

[6] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH220
[7] European Chemicals Agency (ECHA) · 605 reports · DangerH220, H280, H281

First aid

Remove victim to open air. If he is overcome by gas, apply artificial resuscitation. (USCG, 1999)[1]
Eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop. Skin: Caution: Exposure of skin to compressed gases may result in freezing of the skin. Treatment for frostbite may be necessary.[1]
Excerpt from ERG Guide 115 [Gases - Flammable (Including Refrigerated Liquids)]: Refer to the "General First Aid" section. Specific First Aid: Clothing frozen to the skin should be thawed before being removed. In case of contact with liquefied gas, only medical personnel should attempt thawing frosted parts. In case of burns, immediately cool affected skin for as long as possible with cold water. Do not remove clothing if adhering to skin. (ERG, 2024)[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…[8]

Storage

Fireproof. Cool. Ventilation along the floor and ceiling.[3]
Store in a cool, dry, well-ventilated location. Separate from halogens and oxygen. Outside or detached storage is preferred.[4]
Protect against physical damage. ... Isolate from oxidizing agents. Prohibit open flame. Inspect for leakage occasionally.[4]

Incompatibilities

... Reacts with chlorine and bromine in light (explosively in direct sunlight)[4]
Explosive reactions occur upon ignition of mixtures of nitrogen trifluoride with good reducing agents such as ... Methane.[4]
Liquid oxygen gives an explosive mixture when combined with liquid methane.[4]
The reaction of chlorine and methane is explosive at room temperature over yellow mercuric oxide.[4]

Safety data sheets on the supplier’s page: Sigma-Aldrich, Thermo Fisher Scientific, Alfa Chemistry.

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]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[5]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[6]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
[7]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[8]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[9]NMRShiftDB · Linked only · via PubChem · retrieved 2026-10-14
[10]Human Metabolome Database (HMDB) · Linked only · via PubChem · retrieved 2026-10-14
[11]SpectraBase · Linked only · via PubChem · retrieved 2026-10-14
[12]MassBank of North America (MoNA) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[13]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[14]MassBank Europe · 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.