Carbon monoxide

Carbon monoxide (chemical formula CO) is a colorless, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom. It is the simplest molecule of the oxocarbon family. In coordination complexes the carbon monoxide ligand is called carbonyl.

Carbon monoxide
Ball-and-stick model of carbon monoxide
Spacefill model of carbon monoxide
Names
Preferred IUPAC name
Carbon monoxide
Other names
Carbonic Oxide
Carbon Protoxide
oxide of carbon
protoxide of carbon
Carbon mono-oxide
Carbonous Oxide
carbonei oxidum
oxyde de carbone
Carbon(II) oxide
carbonii halitus
carboneum oxgenisatum
Carbate
Carbonyl
Kohlenoxyd

Water gas
Flue gas
carbonic inflammable air
heavy inflammable air
hydrocarbonate
carbonated hydrogene
white damp
fire damp
powder gas
illuminating gas
Dowson gas
Mond gas
power gas
producer gas
blast furnace gas
coal gas
phlogiston
Identifiers
3D model (JSmol)
3587264
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.010.118
EC Number
  • 211-128-3
421
KEGG
MeSH Carbon+monoxide
RTECS number
  • FG3500000
UNII
UN number 1016
  • InChI=1S/CO/c1-2 Y
    Key: UGFAIRIUMAVXCW-UHFFFAOYSA-N Y
  • InChI=1/CO/c1-2
    Key: UGFAIRIUMAVXCW-UHFFFAOYAT
  • [C-]#[O+]
Properties
CO
Molar mass 28.010 g/mol
Appearance Colorless gas
Odor Odorless
Density
  • 789 kg/m3, liquid
  • 1.250 kg/m3 at 0 °C, 1 atm
  • 1.145 kg/m3 at 25 °C, 1 atm
Melting point −205.02 °C (−337.04 °F; 68.13 K)
Boiling point −191.5 °C (−312.7 °F; 81.6 K)
27.6 mg/L (25 °C)
Solubility soluble in chloroform, acetic acid, ethyl acetate, ethanol, ammonium hydroxide, benzene
1.04 atm·m3/mol
−9.8·10−6 cm3/mol
1.0003364
0.122 D
Thermochemistry
29.1 J/(K·mol)
197.7 J/(K·mol)
−110.5 kJ/mol
−283.4 kJ/mol
Pharmacology
V04CX08 (WHO)
Hazards
Safety data sheet See: data page
ICSC 0023
GHS pictograms
GHS Signal word Danger
H220, H331, H360, H372
P201, P202, P210, P260, P261, P264, P270, P271, P281, P304+340, P308+313, P311, P314, P321, P377, P381, P403, P403+233, P405, P501
NFPA 704 (fire diamond)
Flash point −191 °C (−311.8 °F; 82.1 K)
609 °C (1,128 °F; 882 K)
Explosive limits 12.5–74.2%
Lethal dose or concentration (LD, LC):
  • 8636 ppm (rat, 15 min)
  • 5207 ppm (rat, 30 min)
  • 1784 ppm (rat, 4 h)
  • 2414 ppm (mouse, 4 h)
  • 5647 ppm (guinea pig, 4 h)[2]
  • 4000 ppm (human, 30 min)
  • 5000 ppm (human, 5 min)[2]
NIOSH (US health exposure limits):[3]
PEL (Permissible)
TWA 50 ppm (55 mg/m3)
REL (Recommended)
  • TWA 35 ppm (40 mg/m3)
  • C 200 ppm (229 mg/m3)
IDLH (Immediate danger)
1200 ppm
Related compounds
Related carbon oxides
Carbon dioxide
Carbon suboxide
Oxocarbons
Supplementary data page
Refractive index (n),
Dielectric constantr), etc.
Thermodynamic
data
Phase behaviour
solidliquidgas
UV, IR, NMR, MS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Thermal combustion is the most common source of carbon monoxide, however there are numerous environmental and biological sources that generate and emit a significant amount of carbon monoxide. Humans utilize carbon monoxide for various industrial processes including synthetic chemical manufacturing and metallurgy, however it is also a problematic air pollutant arising from industrial activities. Upon emission into the atmosphere, carbon monoxide may have roles potentially affecting climate change.

Carbon monoxide has important biological roles across phylogenetic kingdoms. In mammalian physiology, carbon monoxide is a classical example of hormesis where low concentrations serve as an endogenous neurotransmitter (gasotransmitter) and high concentrations are toxic resulting in carbon monoxide poisoning.