Carbon monoxide - Wikipedia, the free encyclopedia
For the song by Cake, see Carbon Monoxide (Cake song).Carbon monoxide
numberFG3500000Beilstein Reference3587264Gmelin Reference421Jmol-3D imagesImage 1SMILES
PropertiesMolecular formulaCOMolar mass28.010 g/molAppearancecolorless gasOdorodorlessDensity789 kg/m3, liquid
1.250 kg/m3 at 0 ?C, 1 atm
1.145 kg/m3 at 25 ?C, 1 atmMelting point-205.02 ?C; -337.04 ?F; 68.13 KBoiling point-191.5 ?C; -312.7 ?F; 81.6 KSolubility in water27.6 mg/1 L (25 ?C)Solubilitysoluble in chloroform, acetic acid,
ethyl acetate, ethanol, ammonium hydroxide, benzenekH1.04 atm-m3/molRefractive index (nD)1.0003364Dipole moment0.122 DThermochemistrySpecific
heat capacity C29.1 J/K molStd molar
entropy So298197.7 J?mol-1?K-1Std enthalpy of
formation ?fHo298-110.5 kJ?mol-1Std enthalpy of
combustion ?cHo298-283.4 kJ/molHazardsMSDSExternal MSDSEU Index006-001-00-2EU classification
T+R-phrasesR61 R12 R26 R48/23S-phrasesS53 S45NFPA 704
point-191.0 ?C; -311.8 ?F; 82.1 KAutoignition temperature609 ?C; 1,128 ?F; 882 KExplosive limits12.5-74.2%Related compoundsRelated carbon oxidesCarbon dioxide
OxocarbonsSupplementary data pageStructure and
propertiesn, ?r, etc.Thermodynamic
Solid, liquid, gasSpectral dataUV, IR, NMR, MS
Y (verify) (what
Except where noted otherwise, data are given for materials in their standard state (at 25 ?C (77 ?F), 100 kPa)Infobox references
Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is toxic to humans and animals when encountered in higher concentrations, although it is also
produced in normal animal metabolism in low quantities, and is thought to have some normal biological functions. In the atmosphere, it is spatially variable and short lived, having a role in the
formation of ground-level ozone.
Carbon monoxide consists of one carbon atom and one oxygen atom, connected by a triple bond that consists of two covalent bonds as well as one dative covalent bond. It is the simplest oxocarbon, and
isoelectronic with the cyanide ion and molecular nitrogen. In coordination complexes the carbon monoxide ligand is called carbonyl.
Carbon monoxide is produced from the partial oxidation of carbon-containing compounds; it forms when there is not enough oxygen to produce carbon dioxide (CO2), such as when operating a stove or an
internal combustion engine in an enclosed space. In the presence of oxygen, including atmospheric concentrations, carbon monoxide burns with a blue flame, producing carbon dioxide.Coal gas, which
was widely used before the 1960s for domestic lighting, cooking, and heating, had carbon monoxide as a significant fuel constituent. Some processes in modern technology, such as iron smelting, still
produce carbon monoxide as a byproduct.
Worldwide, the largest source of carbon monoxide is natural in origin, due to photochemical reactions in the troposphere that generate about 5x1012 kilograms per year. Other natural sources of CO
include volcanoes, forest fires, and other forms of combustion.
In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on the heme from hemoglobin breakdown. This process produces a certain amount of carboxyhemoglobin in normal
persons, even if they do not breathe any carbon monoxide. Following the first report that carbon monoxide is a normal neurotransmitter in 1993, as well as one of three gases that naturally
modulate inflammatory responses in the body (the other two being nitric oxide and hydrogen sulfide), carbon monoxide has received a great deal of clinical attention as a biological regulator. In many
tissues, all three gases are known to act as anti-inflammatories, vasodilators, and promoters of neovascular growth. Clinical trials of small amounts of carbon monoxide as a drug are
Contents1 History2 Molecular properties2.1 Bonding and dipole moment2.2 Bond polarity and oxidation state3 Biological and physiological properties3.1 Toxicity3.2 Normal human physiology3.3
Microbiology4 Occurrence4.1 Atmospheric presence4.2 Urban pollution4.2.1 Role in ground-level ozone formation4.3 Indoor pollution4.4 Blood presence4.5 Astrophysics5 Production5.1 Industrial
production5.2 Laboratory preparation6 Coordination chemistry7 Organic and main group chemistry8 Uses8.1 Chemical industry8.2 Meat coloring8.3 Medicine8.4 Lasers9 See also10 References11 External
Aristotle (384-322 BC) first recorded that burning coals emanated toxic fumes. An ancient method of execution was to shut the criminal in a bathing room with smouldering coals. What was not known was
the mechanism of death. Greek physician Galen (129-199 AD) speculated that there was a change in the composition of the air that caused harm when inhaled. In 1776, the French chemist de Lassone
produced CO by heating zinc oxide with coke, but mistakenly concluded that the gaseous product was hydrogen, as it burned with a blue flame. The gas was identified as a compound containing carbon and
oxygen by the Scottish chemist William Cumberland Cruikshank in the year 1800. Its toxic properties on dogs were thoroughly investigated by Claude Bernard around 1846.
During World War II, a gas mixture including carbon monoxide was used to keep motor vehicles running in parts of the world where gasoline and diesel fuel were scarce. External (with a few exceptions)
charcoal or wood gas generators were fitted, and the mixture of atmospheric nitrogen, carbon monoxide, and small amounts of other gases produced by gasification was piped to a gas mixer. The gas
mixture produced by this process is known as wood gas. Carbon monoxide was also used on a large scale during the Holocaust at some Nazi extermination camps, the most notable by gas vans in Chelmno,
and in the Action T4 "euthanasia" program.
Carbon monoxide has a molar mass of 28.0, which makes it slightly lighter than air, whose average molar mass is 28.8. According to the ideal gas law, CO is therefore less dense than air. Neither gas
is "ideal", however, so neither has exactly the density predicted by the ideal gas law.
The bond length between the carbon atom and the oxygen atom is 112.8 pm. This bond length is consistent with a triple bond, as in molecular nitrogen (N2), which has a similar bond length and
nearly the same molecular mass. Carbon-oxygen double bonds are significantly longer, 120.8 pm in formaldehyde, for example. The boiling point (82 K) and melting point (68 K) are very similar to
those of N2 (77 K and 63 K, respectively). The bond dissociation energy of 1072 kJ/mol is stronger than that of N2 (942 kJ/mol) and represents the strongest chemical bond known.
The ground electronic state of carbon monoxide is a singlet state since there are no unpaired electrons.
Bonding and dipole moment
Carbon and oxygen together have a total of 10 valence electrons in carbon monoxide. To satisfy the octet rule for the carbon, the two atoms form a triple bond, with six shared electrons in three
bonding molecular orbitals, rather than the usual double bond found in organic carbonyl compounds. Since four of the shared electrons come from the oxygen atom and only two from carbon, one bonding
orbital is occupied by two electrons from oxygen, forming a dative or dipolar bond. This causes a C O polarization, since oxygen is more electronegative than carbon. In the free carbon monoxide, a
net negative charge ?- remains at the carbon end and the molecule has a small dipole moment of 0.122 D.
The molecule is therefore asymmetric: oxygen has more electron density than carbon, and is also slightly positively charged compared to carbon being negative. By contrast, the isoelectronic
dinitrogen molecule has no dipole moment.
If carbon monoxide acts as a ligand, the polarity of the dipole may reverse with a net negative charge on the oxygen end, depending on the structure of the coordination complex. See also the
section "Coordination chemistry" below.
Bond polarity and oxidation state
Theoretical and experimental studies show that, despite the greater electronegativity of oxygen, the dipole moment points from the more-negative carbon end to the more-positive oxygen end.
The three bonds are in fact polar covalent bonds that are strongly polarized. The calculated polarization toward the oxygen atom is 71% for the ?-bond and 77% for both ?-bonds.
The oxidation state of carbon in carbon monoxide is +2 in each of these structures. It is calculated by counting all the bonding electrons as belonging to the more electronegative oxygen. Only the
two non-bonding electrons on carbon are assigned to carbon. In this count, carbon then has only two valence electrons in the molecule compared to four in the free atom.
Biological and physiological properties
ToxicityMain article: Carbon monoxide poisoning
Carbon monoxide poisoning is the most common type of fatal air poisoning in many countries. Carbon monoxide is colorless, odorless, and tasteless, but highly toxic. It combines with hemoglobin to
produce carboxyhemoglobin, which usurps the space in hemoglobin that normally carries oxygen, but is ineffective for delivering oxygen to bodily tissues. Concentrations as low as 667 ppm may cause up
to 50% of the body's hemoglobin to convert to carboxyhemoglobin. A level of 50% carboxyhemoglobin may result in seizure, coma, and fatality. In the United States, the OSHA limits long-term
workplace exposure levels above 50 ppm. Within short time scales, carbon monoxide absorption is cumulative, since the half-life is about 5 h in fresh air (see main article).
The most common symptoms of carbon monoxide poisoning may resemble other types of poisonings and infections, including symptoms such as headache, nausea, vomiting, dizziness, fatigue, and a feeling
of weakness. Affected families often believe they are victims of food poisoning. Infants may be irritable and feed poorly. Neurological signs include confusion, disorientation, visual disturbance,
syncope and seizures.
Some descriptions of carbon monoxide poisoning include retinal hemorrhages, and an abnormal cherry-red blood hue. In most clinical diagnoses these signs are seldom noticed. One difficulty
with the usefulness of this cherry-red effect is that it corrects, or masks, what would otherwise be an unhealthy appearance, since the chief effect of removing deoxygenated hemoglobin is to make an
asphyxiated person appear more normal, or a dead person appear more lifelike, similar to the effect of red colorants in embalming fluid. The "false" or unphysiologic red-coloring effect in anoxic
CO-poisoned tissue is related to the meat-coloring commercial use of carbon monoxide, discussed below.
Carbon monoxide also binds to other molecules such as myoglobin and mitochondrial cytochrome oxidase. Exposures to carbon monoxide may cause significant damage to the heart and central nervous
system, especially to the globus pallidus, often with long-term chronic pathological conditions. Carbon monoxide may have severe adverse effects on the fetus of a pregnant woman.
Normal human physiology
Carbon monoxide is produced naturally by the human body as a signaling molecule. Thus, carbon monoxide may have a physiological role in the body, such as a neurotransmitter or a blood vessel
relaxant. Because of carbon monoxide's role in the body, abnormalities in its metabolism have been linked to a variety of diseases, including neurodegenerations, hypertension, heart failure, and
Carbon monoxide is a nutrient for methanogenic bacteria, a building-block for acetylcoenzyme A. This is the theme for the emerging field of bioorganometallic chemistry. Extremophile
micro-organisms can, thus, metabolise carbon monoxide in such locations as the thermal vents of volcanoes.
In bacteria, carbon monoxide is produced via the reduction of carbon dioxide by the enzyme carbon monoxide dehydrogenase, an Fe-Ni-S-containing protein.
CooA is a carbon monoxide sensor protein. The scope of its biological role is still unknown; it may be part of a signaling pathway in bacteria and archaea. Its occurrence in mammals is not
Monthly averages of global concentrations of tropospheric carbon monoxide at an altitude
of about 12,000 feet. Data were collected by the MOPITT (Measurements Of Pollution In The Troposphere) sensor on NASA's Terra satellite.
Carbon monoxide occurs in various natural and artificial environments. Typical concentrations in parts per million are as follows:
Composition of dry atmosphere, by volumeppmv: parts per million by volume (note: volume fraction is equal to mole fraction for ideal gas only, see volume (thermodynamics))ConcentrationSource0.1
ppmvNatural atmosphere level (MOPITT)0.5-5 ppmvAverage level in homes5-15 ppmvNear-properly adjusted gas stoves in homes, modern vehicle exhaust emissions17 ppmvAtmosphere of Venus100-200
ppmvExhaust from automobiles in the Mexico City central area700 ppmvAtmosphere of Mars5,000 ppmvExhaust from a home wood fire7,000 ppmvUndiluted warm car exhaust without a catalytic
The streak of red, orange, and yellow across South America, Africa, and the Atlantic Ocean
in this animation points to high levels of carbon monoxide on September 30, 2005.
Carbon Monoxide concentrations in Northern Hemisphere spring as measured with the MOPITT instrument.
Carbon monoxide is present in small amounts in the atmosphere, chiefly as a product of volcanic activity but also from natural and man-made fires (such as forest and bushfires, burning of crop
residues, and sugarcane fire-cleaning). The burning of fossil fuels also contributes to carbon monoxide production. Carbon monoxide occurs dissolved in molten volcanic rock at high pressures in the
Earth's mantle. Because natural sources of carbon monoxide are so variable from year to year, it is extremely difficult to accurately measure natural emissions of the gas.
Carbon monoxide has an indirect radiative forcing effect by elevating concentrations of methane and tropospheric ozone through chemical reactions with other atmospheric constituents (e.g., the
hydroxyl radical, OH.) that would otherwise destroy them. Through natural processes in the atmosphere, it is eventually oxidized to carbon dioxide. Carbon monoxide concentrations are both
short-lived in the atmosphere and spatially variable.
In the atmosphere of Venus carbon monoxide occurs as a result of the photodissociation of carbon dioxide by electromagnetic radiation of wavelengths shorter than 169 nm.
Due to its long lifetime in the mid-troposphere, carbon monoxide is also used as tracer of transport for pollutant plumes.
Carbon monoxide is a temporary atmospheric pollutant in some urban areas, chiefly from the exhaust of internal combustion engines (including vehicles, portable and back-up generators, lawn mowers,
power washers, etc.), but also from incomplete combustion of various other fuels (including wood, coal, charcoal, oil, paraffin, propane, natural gas, and trash).
Large CO pollution events can be observed from space over cities.
Role in ground-level ozone formationMain article: Tropospheric ozone
Carbon monoxide is, along with aldehydes, part of the series of cycles of chemical reactions that form photochemical smog. It reacts with hydroxyl radical (oOH) to produce a radical intermediate
oHOCO, which transfers rapidly its radical hydrogen to O2 to form peroxy radical (HO2o) and carbon dioxide (CO2). Peroxy radical subsequently reacts with nitrogen oxide (NO) to form nitrogen
dioxide (NO2) and hydroxyl radical. NO2 gives O(3P) via photolysis, thereby forming O3 following reaction with O2. Since hydroxyl radical is formed during the formation of NO2, the balance of the
sequence of chemical reactions starting with carbon monoxide and leading to the formation of ozone is:
CO + 2O2 + h? -> CO2 + O3
(where h? refers to the photon of light absorbed by the NO2 molecule in the sequence)
Although the creation of NO2 is the critical step leading to low level ozone formation, it also increases this ozone in another, somewhat mutually exclusive way, by reducing the quantity of NO that
is available to react with ozone.
In closed environments, the concentration of carbon monoxide can easily rise to lethal levels. On average, 170 people in the United States die every year from carbon monoxide produced by
non-automotive consumer products. However, according to the Florida Department of Health, "every year more than 500 Americans die from accidental exposure to carbon monoxide and thousands more
across the U.S. require emergency medical care for non-fatal carbon monoxide poisoning" These products include malfunctioning fuel-burning appliances such as furnaces, ranges, water heaters, and
gas and kerosene room heaters; engine-powered equipment such as portable generators; fireplaces; and charcoal that is burned in homes and other enclosed areas. The American Association of Poison
Control Centers (AAPCC) reported 15,769 cases of carbon monoxide poisoning resulting in 39 deaths in 2007. In 2005, the CPSC reported 94 generator-related carbon monoxide poisoning deaths.
Forty-seven of these deaths were known to have occurred during power outages due to severe weather, including Hurricane Katrina. Still others die from carbon monoxide produced by non-consumer
products, such as cars left running in attached garages. The Centers for Disease Control and Prevention estimates that several thousand people go to hospital emergency rooms every year to be treated
for carbon monoxide poisoning.
Carbon monoxide is absorbed through breathing and enters the blood stream through gas exchange in the lungs. Normal circulating levels in the blood are 0% to 3%, and are higher in smokers. Carbon
monoxide levels cannot be assessed through a physical exam. Laboratory testing requires a blood sample (arterial or venous) and laboratory analysis on a CO-Oximeter. Additionally, a noninvasive
carboxyhemoglobin (SpCO) test method from Pulse CO-Oximetry exists and has been validated compared to invasive methods.
Outside of Earth, carbon monoxide is the second-most common molecule in the interstellar medium, after molecular hydrogen. Because of its asymmetry, the carbon monoxide molecule produces far brighter
spectral lines than the hydrogen molecule, making CO much easier to detect. Interstellar CO was first detected with radio telescopes in 1970. It is now the most commonly used tracer of molecular gas
in general in the interstellar medium of galaxies, as molecular hydrogen can only be detected using ultraviolet light, which requires space telescopes. Carbon monoxide observations provide much of
the information about the molecular clouds in which most stars form.
Beta Pictoris, the second brightest star in the constellation Pictor, shows an excess of infrared emission compared to normal stars of its type, which is caused by large quantities of dust and gas
(including carbon monoxide) near the star.
Many methods have been developed for carbon monoxide's production.
A major industrial source of CO is producer gas, a mixture containing mostly carbon monoxide and nitrogen, formed by combustion of carbon in air at high temperature when there is an excess of carbon.
In an oven, air is passed through a bed of coke. The initially produced CO2 equilibrates with the remaining hot carbon to give CO. The reaction of CO2 with carbon to give CO is described as the
Boudouard reaction. Above 800 ?C, CO is the predominant product:
CO2 + C -> 2 CO (?H = 170 kJ/mol)
Another source is "water gas", a mixture of hydrogen and carbon monoxide produced via the endothermic reaction of steam and carbon:
H2O + C -> H2 + CO (?H = +131 kJ/mol)
Other similar "synthesis gases" can be obtained from natural gas and other fuels.
Carbon monoxide is also a byproduct of the reduction of metal oxide ores with carbon, shown in a simplified form as follows:
MO + C -> M + CO
Since CO is a gas, the reduction process can be driven by heating, exploiting the positive (favorable) entropy of reaction. The Ellingham diagram shows that CO formation is favored over CO2 in high
Carbon monoxide is conveniently produced in the laboratory by the dehydration of formic acid or oxalic acid, for example with sulfuric acid. Another method is heating an intimate mixture
of powdered zinc metal and calcium carbonate, which releases CO and leaves behind zinc oxide and calcium oxide:
Zn + CaCO3 -> ZnO + CaO + CO
Coordination chemistryMain article: metal carbonyl
The HOMO of CO is a ? MO.
The LUMO of CO is a ?*antibonding MO.
Most metals form coordination complexes containing covalently attached carbon monoxide. Only metals in lower oxidation states will complex with carbon monoxide ligands. This is because there must be
sufficient electron density to facilitate back-donation from the metal dxz-orbital, to the ?*molecular orbital from CO. The lone pair on the carbon atom in CO, also donates electron density to the
dx?-y? on the metal to form a sigma bond. This electron donation is also exhibited with the cis effect, or the labilization of CO ligands in the cis position. In nickel carbonyl, Ni(CO)4 forms by the
direct combination of carbon monoxide and nickel metal at room temperature. For this reason, nickel in any tubing or part must not come into prolonged contact with carbon monoxide (corrosion). Nickel
carbonyl decomposes readily back to Ni and CO upon contact with hot surfaces, and this method is used for the industrial purification of nickel in the Mond process.
In nickel carbonyl and other carbonyls, the electron pair on the carbon interacts with the metal; the carbon monoxide donates the electron pair to the metal. In these situations, carbon monoxide is
called the carbonyl ligand. One of the most important metal carbonyls is iron pentacarbonyl, Fe(CO)5:
Many metal-CO complexes are prepared by decarbonylation of organic solvents, not from CO. For instance, iridium trichloride and triphenylphosphine react in boiling 2-methoxyethanol or DMF to afford
Metal carbonyls in coordination chemistry are usually studied using infrared spectroscopy.
Organic and main group chemistry
In the presence of strong acids and water, carbon monoxide reacts with alkenes to form carboxylic acids in a process known as the Koch-Haaf reaction. In the Gattermann-Koch reaction, arenes are
converted to benzaldehyde derivatives in the presence of AlCl3 and HCl. Organolithium compounds (e.g. butyl lithium) react with carbon monoxide, but these reactions have little scientific
Although CO reacts with carbocations and carbanions, it is relatively nonreactive toward organic compounds without the intervention of metal catalysts.
With main group reagents, CO undergoes several noteworthy reactions. Chlorination of CO is the industrial route to the important compound phosgene. With borane CO forms an adduct, H3BCO, which is
isoelectronic with the acylium cation [H3CCO]+. CO reacts with sodium to give products resulting from C-C coupling such as sodium acetylenediolate 2Na+
2. It reacts with molten potassium to give a mixture of an organometallic compound, potassium acetylenediolate 2K+
2, potassium benzenehexolate 6K+
6, and potassium rhodizonate 2K+
The compounds cyclohexanehexone or triquinoyl (C6O6) and cyclopentanepentone or leuconic acid (C5O5), which so far have been obtained only in trace amounts, can be regarded as polymers of carbon
At pressures of over 5 gigapascals, carbon monoxide converts into a solid polymer of carbon and oxygen. This is metastable at atmospheric pressure but is a powerful explosive.
Carbon monoxide is an industrial gas that has many applications in bulk chemicals manufacturing. Large quantities of aldehydes are produced by the hydroformylation reaction of alkenes, carbon
monoxide, and H2. Hydroformylation is coupled to the Shell Higher Olefin Process to give precursors to detergents.
Phosgene, useful for preparing isocyanates, polycarbonates, and polyurethanes, is produced by passing purified carbon monoxide and chlorine gas through a bed of porous activated carbon, which serves
as a catalyst. World production of this compound was estimated to be 2.74 million tonnes in 1989.
CO + Cl2 -> COCl2
Methanol is produced by the hydrogenation of carbon monoxide. In a related reaction, the hydrogenation of carbon monoxide is coupled to C-C bond formation, as in the Fischer-Tropsch process where
carbon monoxide is hydrogenated to liquid hydrocarbon fuels. This technology allows coal or biomass to be converted to diesel.
In the Monsanto process, carbon monoxide and methanol react in the presence of a homogeneous rhodium catalyst and hydroiodic acid to give acetic acid. This process is responsible for most of the
industrial production of acetic acid.
An industrial scale use for pure carbon monoxide is purifying nickel in the Mond process.
Carbon monoxide is used in modified atmosphere packaging systems in the US, mainly with fresh meat products such as beef, pork, and fish to keep them looking fresh. The carbon monoxide combines with
myoglobin to form carboxymyoglobin, a bright-cherry-red pigment. Carboxymyoglobin is more stable than the oxygenated form of myoglobin, oxymyoglobin, which can become oxidized to the brown pigment
metmyoglobin. This stable red color can persist much longer than in normally packaged meat. Typical levels of carbon monoxide used in the facilities that use this process are between 0.4% to
The technology was first given "generally recognized as safe" (GRAS) status by the U.S. Food and Drug Administration (FDA) in 2002 for use as a secondary packaging system, and does not require
labeling. In 2004 the FDA approved CO as primary packaging method, declaring that CO does not mask spoilage odor. Despite this ruling, the process remains controversial for fears that it masks
spoilage. In 2007 a bill was introduced to the United States House of Representatives to label modified atmosphere carbon monoxide packaging as a color additive, but the bill died in
subcommittee. The process is banned in many other countries, including Japan, Singapore, and the European Union.
In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on the heme from hemoglobin breakdown. This process produces a certain amount of carboxyhemoglobin in normal
persons, even if they do not breathe any carbon monoxide.
Following the first report that carbon monoxide is a normal neurotransmitter in 1993, as well as one of three gases that naturally modulate inflammatory responses in the body (the other two
being nitric oxide and hydrogen sulfide), carbon monoxide has received a great deal of clinical attention as a biological regulator. In many tissues, all three gases are known to act as
anti-inflammatories, vasodilators, and encouragers of neovascular growth. However, the issues are complex, as neovascular growth is not always beneficial, since it plays a role in tumor growth,
and also the damage from wet macular degeneration, a disease for which smoking (a major source of carbon monoxide in the blood, several times more than natural production) increases the risk from 4
to 6 times.
There is a theory that, in some nerve cell synapses, when long-term memories are being laid down, the receiving cell makes carbon monoxide, which back-transmits to the transmitting cell, telling it
to transmit more readily in future. Some such nerve cells have been shown to contain guanylate cyclase, an enzyme that is activated by carbon monoxide.
Studies involving carbon monoxide have been conducted in many laboratories throughout the world for its anti-inflammatory and cytoprotective properties. These properties have potential to be used to
prevent the development of a series of pathological conditions including ischemia reperfusion injury, transplant rejection, atherosclerosis, severe sepsis, severe malaria, or autoimmunity. Clinical
tests involving humans have been performed, however the results have not yet been released.
Carbon monoxide has also been used as a lasing medium in high-powered infrared lasers.
See alsoMetal carbonylBoudouard reactionCarbon monoxide (data page)Carbon monoxide breath monitorCarbon monoxide detectorCarbon monoxide poisoningCriteria air contaminantsList of highly toxic
gasesMolecular cloudUndersea and Hyperbaric Medical Society - hyperbaric treatment for CO poisoningRubicon Foundation research articles on CO poisoningGuanylate cyclaseBridging carbonyl
References^ Thompson, Mike. Carbon Monoxide - Molecule of the Month, Winchester College, UK.^ Ayres, Robert U. and Ayres, Edward H. (2009). Crossing the Energy Divide: Moving from Fossil Fuel
Dependence to a Clean-Energy Future. Wharton School Publishing. p. 36. ISBN 0-13-701544-5. ^ Weinstock, B.; Niki, H. (1972). "Carbon Monoxide Balance in Nature". Science 176 (4032): 290-2.
Bibcode:1972Sci...176..290W. doi:10.1126/science.176.4032.290. PMID 5019781. ^ a b Verma, A; Hirsch, D.; Glatt, C.; Ronnett, G.; Snyder, S. (1993). "Carbon monoxide: A putative neural messenger".
Science 259 (5093): 381-4. Bibcode:1993Sci...259..381V. doi:10.1126/science.7678352. PMID 7678352. ^ a b c Kolata, Gina (January 26, 1993). "Carbon Monoxide Gas Is Used by Brain Cells As a
Neurotransmitter". The New York Times. Retrieved May 2, 2010. ^ a b Li, L; Hsu, A; Moore, PK (2009). "Actions and interactions of nitric oxide, carbon monoxide and hydrogen sulphide in the
cardiovascular system and in inflammation--a tale of three gases!". Pharmacology & therapeutics 123 (3): 386-400. doi:10.1016/j.pharmthera.2009.05.005. PMID 19486912. ^ a b Johnson, Carolyn Y.
(October 16, 2009). "Poison gas may carry a medical benefit". The Boston Globe. Retrieved October 16, 2009. ^ Penney, David G. (2000) Carbon Monoxide Toxicity, CRC Press, p. 5, ISBN 0-8493-2065-8.^
Cruickshank, W. (1801) "Some observations on different hydrocarbonates and combinations of carbone with oxygen, etc. in reply to some of Dr. Priestley's late objections to the new system of
chemistry," Journal of Natural Philosophy, Chemistry and the Arts [a.k.a. Nicholson's Journal], 1st series, 5 : 1-9.^ Cruickshank, W. (1801) "Some additional observations on hydrocarbonates, and the
gaseous oxide of carbon," Journal of Natural Philosophy, Chemistry and the Arts, 1st series, 5 : 201-211.^ Waring, Rosemary H.; Steventon, Glyn B. and Mitchell, Steve C. (2007). Molecules of death.
Imperial College Press. p. 38. ISBN 1-86094-814-6. ^ Kitchen, Martin (2006). A history of modern Germany, 1800-2000. Wiley-Blackwell. p. 323. ISBN 1-4051-0041-9. ^ Gilliam, O. R.; Johnson, C. M. and
Gordy, W. (1950). "Microwave Spectroscopy in the Region from Two to Three Millimeters". Physical Review 78 (2): 140. Bibcode:1950PhRv...78..140G. doi:10.1103/PhysRev.78.140. ^ Haynes, William M.
(2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton, Florida: CRC Press. p. 9-33. ISBN 978-1439820773. ^ Haynes, William M. (2010). Handbook of Chemistry and Physics (91 ed.). Boca Raton,
Florida: CRC Press. p. 9-39. ISBN 978-1439820773. ^ Common Bond Energies (D) and Bond Lengths (r). wiredchemist.com^ Vidal, C. R. (28 June 1997). "Highly Excited Triplet States of Carbon Monoxide".
Archived from the original on 2006-08-28. Retrieved August 16, 2012. ^ Scuseria, Gustavo E.; Miller, Michael D.; Jensen, Frank; Geertsen, Jan (1991). "The dipole moment of carbon monoxide". J. Chem.
Phys. 94 (10): 6660. Bibcode:1991JChPh..94.6660S. doi:10.1063/1.460293. ^ Lupinetti, Anthony J.; Fau, Stefan; Frenking, Gernot; Strauss, Steven H. (1997). "Theoretical Analysis of the Bonding between
CO and Positively Charged Atoms". J. Phys. Chem. A 101 (49): 9551-9559. doi:10.1021/jp972657l. ^ Blanco, Fernando; Alkorta, Ibon; Solimannejad, Mohammad; Elguero, Jose (2009). "Theoretical Study of
the 1:1 Complexes between Carbon Monoxide and Hypohalous Acids". J. Phys. Chem. A 113 (13): 3237-3244. doi:10.1021/jp810462h. PMID 19275137. ^ Meerts, W; De Leeuw, F.H.; Dymanus, A. (1 June 1977).
"Electric and magnetic properties of carbon monoxide by molecular-beam electric-resonance spectroscopy". Chemical Physics 22 (2): 319-324. Bibcode:1977CP.....22..319M.
doi:10.1016/0301-0104(77)87016-X. ^ Stefan, Thorsten; Janoschek, Rudolf (2000). "How relevant are S=O and P=O Double Bonds for the Description of the Acid Molecules H2SO3, H2SO4, and H3PO3,
respectively?". Journal of Molecular Modeling 6 (2): 282-288. doi:10.1007/PL00010730. ^ Omaye ST (2002). "Metabolic modulation of carbon monoxide toxicity". Toxicology 180 (2): 139-150.
doi:10.1016/S0300-483X(02)00387-6. PMID 12324190. ^ Tikuisis, P; Kane, DM; McLellan, TM; Buick, F; Fairburn, SM (1992). "Rate of formation of carboxyhemoglobin in exercising humans exposed to carbon
monoxide". Journal of Applied Physiology 72 (4): 1311-9. PMID 1592720. ^ "OSHA CO guidelines". OSHA. Retrieved May 2009. ^ a b Blumenthal, Ivan (1 June 2001). "Carbon monoxide poisoning". J R Soc Med
(The Royal Society of Medicine) 94 (6): 270-272. PMC 1281520. PMID 11387414. ^ Ganong, William F (2005). "37". Review of medical physiology (22 ed.). McGraw-Hill. p. 684. ISBN 0-07-144040-2.
Retrieved May 2009. ^ Prockop LD, Chichkova RI (2007). "Carbon monoxide intoxication: an updated review". J Neurol Sci 262 (1-2): 122-130. doi:10.1016/j.jns.2007.06.037. PMID 17720201. ^ Tucker
Blackburn, Susan (2007). Maternal, fetal, & neonatal physiology: a clinical perspective. Elsevier Health Sciences. p. 325. ISBN 1-4160-2944-3. ^ a b Wu, L; Wang, R (December 2005). "Carbon
Monoxide: Endogenous Production, Physiological Functions, and Pharmacological Applications". Pharmacol Rev 57 (4): 585-630. doi:10.1124/pr.57.4.3. PMID 16382109. ^ Thauer, R. K. (1998). "Biochemistry
of methanogenesis: a tribute to Marjory Stephenson. 1998 Marjory Stephenson Prize Lecture" (Free). Microbiology 144 (9): 2377-2406. doi:10.1099/00221287-144-9-2377. PMID 9782487. ^ Hogan, C. Michael
(2010). "Extremophile" in E. Monosson and C. Cleveland (eds.). Encyclopedia of Earth. National Council for Science and the Environment, Washington, DC^ Jaouen, G., ed. (2006). Bioorganometallics:
Biomolecules, Labeling, Medicine. Weinheim: Wiley-VCH. ISBN 3-527-30990-X. ^ Roberts, G. P.; Youn, H.; Kerby, R. L. (2004). "CO-Sensing Mechanisms". Microbiology and Molecular Biology Reviews 68 (3):
453-473. doi:10.1128/MMBR.68.3.453-473.2004. PMC 515253. PMID 15353565. ^ http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOP_CO_M^ Source for figures: Carbon dioxide, NOAA Earth System
Research Laboratory, (updated 2010.06). Methane, IPCC TAR table 6.1, (updated to 1998). The NASA total was 17 ppmv over 100%, and CO2 was increased here by 15 ppmv. To normalize, N2 should be reduced
by about 25 ppmv and O2 by about 7 ppmv.^ Committee on Medical and Biological Effects of Environmental Pollutants (1977). Carbon Monoxide. Washington, D.C.: National Academy of Sciences. p. 29. ISBN
0-309-02631-8. ^ Green W. "An Introduction to Indoor Air Quality: Carbon Monoxide (CO)". United States Environmental Protection Agency. Retrieved 2008-12-16. ^ a b Gosink, Tom (1983-01-28). "What Do
Carbon Monoxide Levels Mean?". Alaska Science Forum. Geophysical Institute, University of Alaska Fairbanks. Retrieved 2007-12-01. ^ Singer, Siegfried Fred (1975). The Changing Global Environment.
Springer. p. 90. ISBN 9027704023. ^ Gosink T (January 28, 1983). "What Do Carbon Monoxide Levels Mean?". Alaska Science Forum. Geophysical Institute, University of Alaska Fairbanks. Retrieved
December 16, 2008. ^ Sigel, Astrid and Sigel, Roland K. O. (2009). Metal-Carbon Bonds in Enzymes and Cofactors. Royal Society of Chemistry. p. 243. ISBN 1-84755-915-8. ^ White, James Carrick et al.
(1989). Global climate change linkages: acid rain, air quality, and stratospheric ozone. Springer. p. 106. ISBN 0-444-01515-9. ^ Pommier, M.; Law, K. S.; Clerbaux, C.; Turquety, S.; Hurtmans, D.;
Hadji-Lazaro, J.; Coheur, P.-F.; Schlager, H.; Ancellet, G.; Paris, J.-D.; N?d?lec, P.; Diskin, G. S.; Podolske, J. R.; Holloway, J. S.; Bernath, P. (2010). "IASI carbon monoxide validation over the
Arctic during POLARCAT spring and summer campaigns". Atmospheric Chemistry and Physics 10 (21): 10655. doi:10.5194/acp-10-10655-2010. ^ Pommier, M.; McLinden, C. A.; Deeter, M. (2013). "Relative
changes in CO emissions over megacities based on observations from space". Geophysical Research Letters 40 (14): 3766. doi:10.1002/grl.50704. edit^ Reeves, Claire E.; Penkett, Stuart A.; Bauguitte,
Stephane; Law, Kathy S.; Evans, Mathew J.; Bandy, Brian J.; Monks, Paul S.; Edwards, Gavin D.; Phillips, Gavin; Barjat, Hannah; Kent, Joss; Dewey, Ken; Schmitgen, Sandra; Kley, Dieter (2002).
"Potential for photochemical ozone formation in the troposphere over the North Atlantic as derived from aircraft observationsduring ACSOE". Journal of Geophysical Research 107 (D23): 4707.
Bibcode:2002JGRD..107.4707R. doi:10.1029/2002JD002415. ^ Ozone and other photochemical oxidants. National Academies. 1977. p. 23. ISBN 0-309-02531-1. ^ a b c U.S Consumer Product Safety Commission,
Carbon Monoxide Questions and Answers, accessed 2009-12-04^ "Tracking Carbon Monoxide". Environmental Public Health Tracking - Florida Dept. of Health. ^ "AAPCC Annual Data Reports 2007". American
Association of Poison Control Centers.^ Centers for Disease Control and Prevention, National Environmental Public Health Tracking Network, Carbon Monoxide Poisoning, accessed 2009-12-04^ Roth D.,
Herkner H., Schreiber W., Hubmann N., Gamper G., Laggner A.N., Havel C. (2011). "Accuracy of Noninvasive Multiwave Pulse Oximetry Compared With Carboxyhemoglobin From Blood Gas Analysis in Unselected
Emergency Department Patients". Annals of Emergency Medicine 58 (1): 74-9. doi:10.1016/j.annemergmed.2010.12.024. PMID 21459480. ^ Combes, Fran?oise (1991). "Distribution of CO in the Milky Way".
Annual Review of Astronomy & Astrophysics 29: 195. Bibcode:1991ARA&A..29..195C. doi:10.1146/annurev.aa.29.090191.001211. ^ Khan, Amina. "Did two planets around nearby star collide? Toxic gas
holds hints". LA Times. Retrieved March 9, 2014. ^ Dent, W.R.F.; Wyatt, M.C.;Roberge, A.; Augereau,J.-C.; Casassus, S.;Corder, S.; Greaves, J.S.; de Gregorio-Monsalvo, I; Hales, A.; Jackson, A.P.;
Hughes, A. Meredith; Lagrange, A.-M; Matthews, B.; Wilner, D. (March 6, 2014). "Molecular Gas Clumps from the Destruction of Icy Bodies in the ? Pictoris Debris Disk". Science (journal).
doi:10.1126/science.1248726. Retrieved March 9, 2014. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 200. ISBN 0-12-352651-5.^ Higman, C; van der Burgt, M (2003).
Gasification. Gulf Professional Publishing. p. 12. ISBN 0-7506-7707-4. ^ a b Koch, H.; Haaf, W. (1973), "1-Adamantanecarboxylic Acid", Org. Synth. ; Coll. Vol. 5: 20 ^ a b Coleman, G. H. and Craig,
David (1943), "p-Tolualdehyde", Org. Synth. ; Coll. Vol. 2: 583 ^ Brauer, Georg (1963). Handbook of Preparative Inorganic Chemistry Vol. 1, 2nd Ed.. Newyork: Academic Press. p. 646. ISBN
978-0121266011. ^ Mond L, Langer K, Quincke F (1890). "Action of carbon monoxide on nickel". Journal of the Chemical Society 57: 749-753. doi:10.1039/CT8905700749. ^ Chatani, N.; Murai, S. "Carbon
Monoxide" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289^ B?chner, W.; Weiss, E. (1964). "Zur Kenntnis der sogenannten
"Alkalicarbonyle" IV ?ber die Reaktion von geschmolzenem Kalium mit Kohlenmonoxid". Helvetica Chimica Acta 47 (6): 1415-1423. doi:10.1002/hlca.19640470604. ^ Fownes, George (1869). A Manual of
elementary chemistry. H.C. Lea. p. 678. ^ Katz, Allen I.; Schiferl, David; Mills, Robert L. (1984). "New phases and chemical reactions in solid carbon monoxide under pressure". The Journal of
Physical Chemistry 88 (15): 3176. doi:10.1021/j150659a007. ^ Evans, W. J.; Lipp, M. J.; Yoo, C.-S.; Cynn, H.; Herberg, J. L.; Maxwell, R. S.; Nicol, M. F. (2006). "Pressure-Induced Polymerization of
Carbon Monoxide: Disproportionation and Synthesis of an Energetic Lactonic Polymer". Chemistry of Materials 18 (10): 2520. doi:10.1021/cm0524446. ^ Elschenbroich, C.; Salzer, A. (2006).
Organometallics: A Concise Introduction (2nd ed.). Weinheim: Wiley-VCH. ISBN 3-527-28165-7. ^ Wolfgang Schneider; Werner Diller (2005), "Phosgene", Ullmann's Encyclopedia of Industrial Chemistry,
Weinheim: Wiley-VCH, doi:10.1002/14356007.a19_411 ^ Sorheim, S, Nissena, H, Nesbakken, T (1999). "The storage life of beef and pork packaged in an atmosphere with low carbon monoxide and high carbon
dioxide". Journal of Meat Science 52 (2): 157-164. doi:10.1016/S0309-1740(98)00163-6. ^ Eilert EJ (2005). "New packaging technologies for the 21st century". Journal of Meat Science 71 (1): 122-127.
doi:10.1016/j.meatsci.2005.04.003. ^ Huffman, Randall D. "Low-Oxygen Packaging with CO: A Study in Food Politics That Warrants Peer Review". FoodSafetyMagazine.com. Retrieved April 18, 2007. ^
"Carbon Monoxide Treated Meat, Poultry, and Seafood Safe Handling, Labeling, and Consumer Protection Act (Introduced in House)". The Library of Congress. ^ "Proof in the Pink? Meat Treated to Give It
Fresh Look". ABC News. November 14, 2007. Retrieved May 27, 2009. ^ Carbon Monoxide in Meat Packaging: Myths and Facts. American Meat Institute. 2008. Retrieved May 2009. ^ "CO in packaged meat".
Carbon Monoxide Kills Campaign. Retrieved November 2012. ^ Ionin, A.; Kinyaevskiy, I.; Klimachev, Y.; Kotkov, A.; Kozlov, A. (2012). "Novel mode-locked carbon monoxide laser system achieves high
accuracy". SPIE Newsroom. doi:10.1117/2.1201112.004016. edit
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vteOxidesVarious StatesAntimony tetroxide (Sb2O4)Cobalt(II,III) oxide (Co3O4)Iron(II,III) oxide (Fe3O4)Lead(II,IV) oxide (Pb3O4)Manganese(II,III) oxide (Mn3O4)Silver(I,III) oxide (AgO)+1 Oxidation
StateCopper(I) oxide (Cu2O)Dicarbon monoxide (C2O)Dichlorine monoxide (Cl2O)Lithium oxide (Li2O)Potassium oxide (K2O)Rubidium oxide (Rb2O)Silver oxide (Ag2O)Thallium(I) oxide (Tl2O)Sodium oxide
(Na2O)Water (hydrogen oxide) (H2O)+2 Oxidation StateAluminium(II) oxide (AlO)Barium oxide (BaO)Beryllium oxide (BeO)Cadmium oxide (CdO)Calcium oxide (CaO)Carbon monoxide (CO)Cobalt(II) oxide
(CoO)Copper(II) oxide (CuO)Iron(II) oxide (FeO)Lead(II) oxide (PbO)Magnesium oxide (MgO)Mercury(II) oxide (HgO)Nickel(II) oxide (NiO)Nitric oxide (NO)Palladium(II) oxide (PdO)Strontium oxide
(SrO)Sulfur monoxide (SO)Disulfur dioxide (S2O2)Tin(II) oxide (SnO)Titanium(II) oxide (TiO)Vanadium(II) oxide (VO)Zinc oxide (ZnO)+3 Oxidation StateAluminium oxide (Al2O3)Antimony trioxide
(Sb2O3)Arsenic trioxide (As2O3)Bismuth(III) oxide (Bi2O3)Boron trioxide (B2O3)Chromium(III) oxide (Cr2O3)Dinitrogen trioxide (N2O3)Erbium(III) oxide (Er2O3)Gadolinium(III) oxide (Gd2O3)Gallium(III)
oxide (Ga2O3)Holmium(III) oxide (Ho2O3)Indium(III) oxide (In2O3)Iron(III) oxide (Fe2O3)Lanthanum oxide (La2O3)Lutetium(III) oxide (Lu2O3)Nickel(III) oxide (Ni2O3)Phosphorus trioxide
(P4O6)Promethium(III) oxide (Pm2O3)Rhodium(III) oxide (Rh2O3)Samarium(III) oxide (Sm2O3)Scandium oxide (Sc2O3)Terbium(III) oxide (Tb2O3)Thallium(III) oxide (Tl2O3)Thulium(III) oxide
(Tm2O3)Titanium(III) oxide (Ti2O3)Tungsten(III) oxide (W2O3)Vanadium(III) oxide (V2O3)Ytterbium(III) oxide (Yb2O3)Yttrium(III) oxide (Y2O3)+4 Oxidation StateCarbon dioxide (CO2)Carbon trioxide
(CO3)Cerium(IV) oxide (CeO2)Chlorine dioxide (ClO2)Chromium(IV) oxide (CrO2)Dinitrogen tetroxide (N2O4)Germanium dioxide (GeO2)Hafnium(IV) oxide (HfO2)Lead dioxide (PbO2)Manganese dioxide
(MnO2)Nitrogen dioxide (NO2)Plutonium dioxide (PuO2)Rhodium(IV) oxide (RhO2)Ruthenium(IV) oxide (RuO2)Selenium dioxide (SeO2)Silicon dioxide (SiO2)Sulfur dioxide (SO2)Tellurium dioxide (TeO2)Thorium
dioxide (ThO2)Tin dioxide (SnO2)Titanium dioxide (TiO2)Tungsten(IV) oxide (WO2)Uranium dioxide (UO2)Vanadium(IV) oxide (VO2)Zirconium dioxide (ZrO2)+5 Oxidation StateAntimony pentoxide (Sb2O5)Arsenic
pentoxide (As2O5)Dinitrogen pentoxide (N2O5)Niobium pentoxide (Nb2O5)Phosphorus pentoxide (P2O5)Tantalum pentoxide (Ta2O5)Vanadium(V) oxide (V2O5)+6 Oxidation StateChromium trioxide
(CrO3)Molybdenum(VI) oxide (MoO3)Rhenium trioxide (ReO3)Selenium trioxide (SeO3)Sulfur trioxide (SO3)Tellurium trioxide (TeO3)Tungsten trioxide (WO3)Uranium trioxide (UO3)Xenon trioxide (XeO3)+7
Oxidation StateDichlorine heptoxide (Cl2O7)Manganese(VII) oxide (Mn2O7)Rhenium(VII) oxide (Re2O7)Technetium(VII) oxide+8 Oxidation StateOsmium tetroxide (OsO4)Ruthenium tetroxide (RuO4)Xenon
tetroxide (XeO4)Iridium tetroxide (IrO4)Hassium tetroxide (HsO4)RelatedOxocarbonSuboxideOxyanionOzonideOxides are sorted by oxidation state. Category:Oxides