Carbon Monoxide

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly lighter 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, 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, 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 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 5 x 1012 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 ongoing.

Read more about Carbon MonoxideHistory, Molecular Properties, Occurrence, Coordination Chemistry, Organic and Main Group Chemistry

Other articles related to "carbon monoxide, carbon":

Snuff - Advantages Over Cigarettes
... Unlike tobacco smoke, snuff is free of tar and harmful gases such as carbon monoxide and nitrogen oxides ... It is not known whether nicotine or carbon monoxide is the major culprit responsible for cigarette-induced coronary heart disease ... If it is carbon monoxide a switch to snuff would reduce the risk substantially, but even if nicotine plays a part our results show that the intake from snuff is no greater than from smoking ...
Carbonyl Metallurgy
... Carbonyls are metal - ligand complexes where carbon monoxide is bonded in a pendant ligand structure to individual atoms of metals such as iron and nickel.) Iron carbonyl is ... Both can be formed by the exposure of the powdered metal to carbon monoxide gas at temperatures of around 75 degrees Celsius ...
Carbon Monoxide - Uses - Medicine
... In biology, carbon monoxide is naturally produced by the action of heme oxygenase 1 and 2 on the heme from hemoglobin breakdown ... 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 ...
Carl D. Keith - Catalytic Converter
... The 1970 amendments to the Clean Air Act required significant reductions in hydrocarbon, carbon monoxide and nitrogen oxide emissions ... the time were oxidation catalysts, which could handle hydrocarbon and carbon monoxide, but were ineffective in reducing nitrogen oxides ... trying to develop a multiple step process that would address hydrocarbons and carbon monoxide in one process while reducing nitrogen oxides in another ...
HR 8799 - Planetary System - Planet Spectra
... Weak methane and carbon monoxide absorption in this planet's atmosphere was also detected, indicating efficient vertical mixing of the atmosphere and a disequilibrium CO/CH4 ratio at the ... Planet b contains ammonia and/or acetylene as well as carbon dioxide, but has little methane Planet c contains ammonia, perhaps some acetylene but neither carbon dioxide nor ... obtained with the Keck telescope, definitively detected carbon monoxide and water absorption lines in the atmosphere of planet c ...