Nitrous oxide

Athanor · official

N₂O · 44.013 g/mol

Also called laughing gas, dinitrogen monoxide, E942

Inorganic

Open in Athanor

Drawn from its SMILES with RDKit

DangerMay cause or intensify fire; oxidizer · Contains gas under pressure; may explode if heated · Contains refrigerated gas; may cause cryogenic burns or injury · May cause drowsiness or dizziness

Names and identifiers

IUPAC name: nitrous oxide
Synonyms: laughing gas, dinitrogen monoxide, E942
+ 38 more
Laughing gas, Dinitrogen oxide, Dinitrogen monoxide, Factitious air, nitrogen protoxide, Nitrogen oxide (N2O), Hyponitrous acid anhydride, Nitrogen hypoxide, Stickdioxyd, oxyde nitreux, Oxido nitroso, Gas, Laughing, protoxyde d'azote, Nitrous oxide, compressed, Oxide, Nitrous, Distickstoffmonoxid, FEMA No. 2779, Nitrogenum oxygenatum, Protoxide of nitrogen, Dinitrogenii oxidum, Nitrogen oxide (n(sub 2)o), INS NO.942, DTXSID8021066, INS-942, K50XQU1029, E-942, CHEBI:17045, diazooxidane, Nitroux Oxide, Nitrous Oxide Sedara, Nitrous Oxide, USP, RefChem:6663, DTXCID301066, 233-032-0, Nitrous oxide [JAN], Lachgas, gaz hilarant, Diazyne 1-oxide
Molecular formula: N₂O
Empirical formula: N₂O
Molecular weight: 44.013 g/mol
Exact mass: 44.00106
CAS number: 10024-97-2
PubChem CID: 948
Canonical SMILES: [N-]=[N+]=O
Isomeric SMILES: [N-]=[N+]=O
InChI: InChI=1S/N2O/c1-2-3
InChIKey: GQPLMRYTRLFLPF-UHFFFAOYSA-N
Molfile

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

Physical properties

TemperaturePressureDensity

Appearance: Colorless gas [Note: Shipped as a liquified compressed gas][6]
7 values
From Hazardous Substances Data Bank (HSDB), the most authoritative source here.
Value As written Source
– Nitrous oxide is a colorless, sweet-tasting gas. It is also known as "laughing gas". Continued breathing of the vapors may impair the decision making process. It is noncombustible but it will accelerate the burning of combustible material in a fire. It is soluble in water. Its vapors are heavier than air. Exposure of the container to prolonged heat or fire can cause it to rupture violently and rocket. It is used as an anesthetic, in pressure packaging, and to manufacture other chemicals. [1] CAMEO Chemicals
– Nitrous oxide, refrigerated liquid appears as a colorless liquid. Density 1.22 g / cm3 at its boiling point of -89 °C. Boils to give a colorless gas that is sweet-smelling and moderately toxic. The gas has narcotic effects when inhaled (laughing gas). Shipped under refrigeration. Vapor pressure is at about 745 psig at 70 °F. Used to freeze foods and to manufacture other chemicals. [1] CAMEO Chemicals
– CBI; Gas Vapor [2] EPA Chemical Data Reporting (CDR)
– COLOURLESS COMPRESSED LIQUEFIED GAS WITH CHARACTERISTIC ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– Colorless gas with a slightly sweet odor. [4] Occupational Safety and Health Administration (OSHA)
– Colorless gas with a slightly sweet odor. [inhalation anesthetic] [Note: Shipped as a liquefied compressed gas.] [5] The National Institute for Occupational Safety and Health (NIOSH)
–shown Colorless gas [Note: Shipped as a liquified compressed gas] [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
Odor: Weak, pleasant odor[6]
Melting point: -90.8 °C (-131.5 °F, USCG 1999)[1]
5 values
4 of 4 sources agree on it (most common value).
Value As written Source
−90.8 °Cshown -131.5 °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.
−91 °C -132 °F (NIOSH, 2024) [1] CAMEO Chemicals
−90.8 °C -90.8 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−90.8 °C -90.8 °C [7] PAC Chemical Database, U.S. Department of Energy
−91 °C -132 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Boiling point: -88.48 °C @760 [mmHg][7]
6 values
5 of 5 sources agree on it (most common value).
Value As written Source
−89.5 °C -129.1 °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.
−88 °C -127 °F at 760 mmHg (NIOSH, 2024) [1] CAMEO Chemicals
−88.5 °C -88.5 °C [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−88 °C -127 °F [4] Occupational Safety and Health Administration (OSHA)
−88.5 °Cshown -88.48 °C @760 [mm Hg] [7] PAC Chemical Database, U.S. Department of Energy
−88 °C -127 °F [5] The National Institute for Occupational Safety and Health (NIOSH)
Density: Density: 1.9775 kg/cu m (gas, 0 °C, 101.3 kPa)[6]
6 values
Only one source reports it.
Value As written Source
– 1.266 at -128.2 °F (USCG, 1999) - Denser 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.
0.0019775 g/mLshown Density: 1.9775 kg/cu m (gas, 0 °C, 101.3 kPa) [6] Hazardous Substances Data Bank (HSDB)cites Theimann M et al; Nitric Acid, Nitrous Acid, and Nitrogen Oxides. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2016). New York, NY: John Wiley & Sons. Online Posting Date: 15 Jun 2000
0.793 g/mL 793 kg/cu m (liquid, 20 °C, 101.3 kPa) [6] Hazardous Substances Data Bank (HSDB)cites Theimann M et al; Nitric Acid, Nitrous Acid, and Nitrogen Oxides. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2016). New York, NY: John Wiley & Sons. Online Posting Date: 15 Jun 2000
– 1.266 at -128.2 °F [4] Occupational Safety and Health Administration (OSHA)
– 1.799 @25 °C [7] PAC Chemical Database, U.S. Department of Energy
– 1.53(relative gas density) [5] The National Institute for Occupational Safety and Health (NIOSH)
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.
Solubility in water: Solubility in water, g/l at 20 °C: 1.2[3]
4 values
From ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative source here.
Value As written Source
– 0.1 % at 77 °F (NIOSH, 2024) [1] CAMEO Chemicals
– 0.1 % at 77 °F (NIOSH, 2024) [1] CAMEO Chemicals
–shown Solubility in water, g/l at 20 °C: 1.2 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– (77 °F): 0.1% [5] The National Institute for Occupational Safety and Health (NIOSH)
log P: log Kow = 0.36[6]
Vapor pressure: 4.29 × 10⁴ mmHg at 25 °C[6]
3 values
Sources disagree; from Hazardous Substances Data Bank (HSDB), the most authoritative.
Value As written Source
42900 mmHgshown 4.29X10+4 mm Hg at 25 °C [6] 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.
38000 mmHg Vapor pressure, kPa at 20 °C: 5060 [3] ILO-WHO International Chemical Safety Cards (ICSCs)
750 mmHg 750 [mm Hg] @-88.7 °C [7] PAC Chemical Database, U.S. Department of Energy
4 more values were reported but failed the checks (unreadable or out of range), so they are not shown.
Viscosity: 0.0145 cP at 25 °C at 101.325 KPa (gas)[6]

Value	As written	Source
–	Nitrous oxide is a colorless, sweet-tasting gas. It is also known as "laughing gas". Continued breathing of the vapors may impair the decision making process. It is noncombustible but it will accelerate the burning of combustible material in a fire. It is soluble in water. Its vapors are heavier than air. Exposure of the container to prolonged heat or fire can cause it to rupture violently and rocket. It is used as an anesthetic, in pressure packaging, and to manufacture other chemicals.	[1] CAMEO Chemicals
–	Nitrous oxide, refrigerated liquid appears as a colorless liquid. Density 1.22 g / cm3 at its boiling point of -89 °C. Boils to give a colorless gas that is sweet-smelling and moderately toxic. The gas has narcotic effects when inhaled (laughing gas). Shipped under refrigeration. Vapor pressure is at about 745 psig at 70 °F. Used to freeze foods and to manufacture other chemicals.	[1] CAMEO Chemicals
–	CBI; Gas Vapor	[2] EPA Chemical Data Reporting (CDR)
–	COLOURLESS COMPRESSED LIQUEFIED GAS WITH CHARACTERISTIC ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	Colorless gas with a slightly sweet odor.	[4] Occupational Safety and Health Administration (OSHA)
–	Colorless gas with a slightly sweet odor. [inhalation anesthetic] [Note: Shipped as a liquefied compressed gas.]	[5] The National Institute for Occupational Safety and Health (NIOSH)
–shown	Colorless gas [Note: Shipped as a liquified compressed gas]	[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

Value	As written	Source
−90.8 °Cshown	-131.5 °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.
−91 °C	-132 °F (NIOSH, 2024)	[1] CAMEO Chemicals
−90.8 °C	-90.8 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−90.8 °C	-90.8 °C	[7] PAC Chemical Database, U.S. Department of Energy
−91 °C	-132 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
−89.5 °C	-129.1 °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.
−88 °C	-127 °F at 760 mmHg (NIOSH, 2024)	[1] CAMEO Chemicals
−88.5 °C	-88.5 °C	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−88 °C	-127 °F	[4] Occupational Safety and Health Administration (OSHA)
−88.5 °Cshown	-88.48 °C @760 [mm Hg]	[7] PAC Chemical Database, U.S. Department of Energy
−88 °C	-127 °F	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	1.266 at -128.2 °F (USCG, 1999) - Denser 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.
0.0019775 g/mLshown	Density: 1.9775 kg/cu m (gas, 0 °C, 101.3 kPa)	[6] Hazardous Substances Data Bank (HSDB)cites Theimann M et al; Nitric Acid, Nitrous Acid, and Nitrogen Oxides. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2016). New York, NY: John Wiley & Sons. Online Posting Date: 15 Jun 2000
0.793 g/mL	793 kg/cu m (liquid, 20 °C, 101.3 kPa)	[6] Hazardous Substances Data Bank (HSDB)cites Theimann M et al; Nitric Acid, Nitrous Acid, and Nitrogen Oxides. Ullmann's Encyclopedia of Industrial Chemistry. 7th ed. (1999-2016). New York, NY: John Wiley & Sons. Online Posting Date: 15 Jun 2000
–	1.266 at -128.2 °F	[4] Occupational Safety and Health Administration (OSHA)
–	1.799 @25 °C	[7] PAC Chemical Database, U.S. Department of Energy
–	1.53(relative gas density)	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
–	0.1 % at 77 °F (NIOSH, 2024)	[1] CAMEO Chemicals
–	0.1 % at 77 °F (NIOSH, 2024)	[1] CAMEO Chemicals
–shown	Solubility in water, g/l at 20 °C: 1.2	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	(77 °F): 0.1%	[5] The National Institute for Occupational Safety and Health (NIOSH)

Value	As written	Source
42900 mmHgshown	4.29X10+4 mm Hg at 25 °C	[6] 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.
38000 mmHg	Vapor pressure, kPa at 20 °C: 5060	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
750 mmHg	750 [mm Hg] @-88.7 °C	[7] PAC Chemical Database, U.S. Department of Energy

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: 3
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 0
H-bond acceptors: 2
Rotatable bonds: 0
TPSA (Å²): 51.2 computed here · PubChem 19.1
Formal charge: 0
XLogP3: 0.5 PubChem
Complexity: 25 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C∞v of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

N63.65%
O36.35%

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: 0.34 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.33 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 4.88 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 44.01
log P ≤ 5 (Crippen): 0.34
H-bond donors ≤ 5: 0
H-bond acceptors ≤ 10: 2

Passes all four rules.

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

Safety

Danger

Most widely reported: 663 company reports to ECHA. Source [8].

Oxidizer
Compressed gas
Harmful or irritant

H270May cause or intensify fire; oxidizer
H280Contains gas under pressure; may explode if heated (56.4% of reports)
H281Contains refrigerated gas; may cause cryogenic burns or injury (40.6% of reports)
H336May cause drowsiness or dizziness (31.7% of reports)

Precautionary statements: P220, P244, P261, P271, P282, P304+P340, P319, P336+P317, P370+P376, P403, P403+P233, P405, P410+P403, P501

View all classifications (2)

[8] European Chemicals Agency (ECHA) · 663 reports · DangerH270, H280, H281, H336
[6] Hazardous Substances Data Bank (HSDB) · DangerH270, H280

Exposure limits

PEL: None[5]
REL-TWA (Time Weighted Average): 25 ppm (46 mg/m³) [waste anesthetic gases only][4]
REL: TWA 25 ppm (46 mg/m3) (TWA over the time exposed) [*Note: REL for exposure to waste anesthetic gas.][5]
TLV: 50 ppm as TWA; A4 (not classifiable as a human carcinogen).[3]
TLV-TWA (Time Weighted Average): 50 ppm [1986][4]
IDLH: N.D. See: IDLH index[5]

First aid

Excerpt from NIOSH Pocket Guide for Nitrous oxide: Eye: Frostbite - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible. Skin: Frostbite - If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water.[1]
Excerpt from NIOSH Pocket Guide for Nitrous oxide: Eye: Frostbite - If eye tissue is frozen, seek medical attention immediately; if tissue is not frozen, immediately and thoroughly flush the eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, lacrimation, or photophobia persist, get medical attention as soon as possible. Skin: Frostbite - If frostbite has occurred, seek medical attention immediately; do NOT rub the affected areas or flush them with water.[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…[9]
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…[9]

Storage

Fireproof if in building. Separated from reducing agents and combustible substances. Cool.[3]
Keep container tightly closed in a dry and well-ventilated place. Contents under pressure.[6]
Store in a location separate from other materials, especially flammables and combustibles. ... Nitrous oxide must be stored to avoid contact with organic peroxides, ammonia, carbon monoxide, hydrogen, hydrogen sulfide, and phosphine, since violent reactions occur. Cylinders of nitrous oxide should be stored in a cool, preferably fire-resistant area, away from heat sources.[6]
Cylinders containing 50% nitrous oxide and 50% oxygen should be protected from the cold to prevent separation of the gases. Cylinders exposed to temperatures lower than -7 °C should be rolled at room temperature to ensure mixing or alternatively stores horizontally for 24 hours at a temperature of not less than 10 °C.[6]

Incompatibilities

Incompatible materials: Aluminum, Borane/boron oxides, Hydrazine, Strong reducing agents[6]
Violent reactions with organic peroxides, hydrazine, hydrogen, hydrogen sulfide, lithium, boron, lithium hydride, sodium, aluminum, phosphine ... Strong oxidizer above 300 °C ...[6]
Powdered aluminum burns in the vapor of ... Nitrous oxide ... .[6]
Spontaneous ignition occurs when nitrous oxide and lithium hydride or hydrazine are mixed.[6]

Safety data sheets on the supplier’s page: AA BLOCKS, Angene Chemical, Shenghe Chemical.

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

Spectra

GC-MSNIST Mass Spectrometry Data Center · NIST Mass Spectrometry Data Center · SpectraBase
Vapor Phase IRSpectraBase (DIGILAB FTS-14 · Vapor Phase)

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]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[9]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
[10]NIST Mass Spectrometry Data Center · Linked only · via PubChem · retrieved 2026-10-14
[11]SpectraBase · 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.