Editing Carbon (section)

===Inorganic compounds===
Commonly carbon-containing compounds which are associated with minerals or which do not contain bonds to the other carbon atoms, halogens, or hydrogen, are treated separately from classical organic compounds; the definition is not rigid, and the classification of some compounds can vary from author to author (see reference articles above). Among these are the simple oxides of carbon. The most prominent oxide is carbon dioxide ({{CO2}}). This was once the principal constituent of the [[paleoatmosphere]], but is a minor component of the [[Earth's atmosphere]] today.<ref>{{cite journal |date=1982 |title=The prebiological paleoatmosphere: stability and composition |journal=Origins of Life and Evolution of Biospheres |volume=12 |pages=245–259 |doi=10.1007/BF00926894 |pmid=7162799 |issue=3 |bibcode=1982OrLi...12..245L |s2cid=20097153 |last1=Levine |first1=Joel S. |last2=Augustsson |first2=Tommy R. |last3=Natarajan |first3=Murali}}</ref> Dissolved in water, it forms [[carbonic acid]] ({{chem|H|2|C|O|3}}), but as most compounds with multiple single-bonded oxygens on a single carbon it is unstable.<ref>{{cite journal |author=Loerting, T. |author1-link=Thomas Loerting |date=2001 |title=On the Surprising Kinetic Stability of Carbonic Acid |journal=Angew. Chem. Int. Ed. |volume=39 |pages=891–895 |doi=10.1002/(SICI)1521-3773(20000303)39:5<891::AID-ANIE891>3.0.CO;2-E |pmid=10760883 |issue=5 |display-authors=1 |last2=Tautermann |first2=Christofer |last3=Kroemer |first3=Romano T. |last4=Kohl |first4=Ingrid |last5=Hallbrucker |first5=Andreas |last6=Mayer |first6=Erwin |last7=Liedl |first7=Klaus R.}}</ref> Through this intermediate, though, resonance-stabilized carbonate [[ion]]s are produced. Some important minerals are carbonates, notably [[calcite]]. [[Carbon disulfide]] ({{chem|C|S|2}}) is similar.{{sfn|Greenwood|Earnshaw|1997|pages=289-292}}

The other common oxide is carbon monoxide (CO). It is formed by incomplete combustion, and is a colorless, odorless gas. The molecules each contain a triple bond and are fairly [[polar molecule|polar]], resulting in a tendency to bind permanently to hemoglobin molecules, displacing oxygen, which has a lower binding affinity.<ref>{{cite journal |author=Haldane J. |date=1895 |title=The action of carbonic oxide on man |journal=Journal of Physiology |volume=18 |pages=430–462 |pmid=16992272 |issue=5–6 |pmc=1514663 |doi=10.1113/jphysiol.1895.sp000578}}</ref><ref>{{cite journal |date=2003 |title=The clinical toxicology of carbon monoxide |journal=Toxicology |issue=1 |pages=25–38 |volume=187 |pmid=12679050 |doi=10.1016/S0300-483X(03)00005-2 |last1=Gorman |first1=D. |last2=Drewry |first2=A. |last3=Huang |first3=Y. L. |last4=Sames |first4=C.|bibcode=2003Toxgy.187...25G }}</ref> [[Cyanide]] (CN{{sup|−}}), has a similar structure, but behaves much like a [[halide]] ion ([[pseudohalogen]]). For example, it can form the nitride [[cyanogen]] molecule ((CN){{sub|2}}), similar to diatomic halides. Likewise, the heavier analog of cyanide, [[cyaphide]] (CP{{sup|−}}), is also considered inorganic, though most simple derivatives are highly unstable. Other uncommon oxides are [[carbon suboxide]] ({{chem|C|3|O|2}}),<ref>{{cite web |title=Compounds of carbon: carbon suboxide |url=http://www.webelements.com/webelements/compounds/text/C/C3O2-504643.html |access-date=2007-12-03 |url-status=live |archive-url=https://web.archive.org/web/20071207230312/http://www.webelements.com/webelements/compounds/text/C/C3O2-504643.html |archive-date=2007-12-07}}</ref> the unstable [[dicarbon monoxide]] (C{{sub|2}}O),<ref>{{cite journal |last1=Bayes |first1=K. |title=Photolysis of Carbon Suboxide |journal=[[Journal of the American Chemical Society]] |volume=83 |date=1961 |pages=3712–3713 |doi=10.1021/ja01478a033 |issue=17|bibcode=1961JAChS..83.3712B }}</ref><ref>{{cite journal |author=Anderson D. J. |title=Photodissociation of Carbon Suboxide |journal=[[Journal of Chemical Physics]] |volume=94 |date=1991 |pages=7852–7867 |issue=12 |bibcode=1991JChPh..94.7857A |doi=10.1063/1.460121 |last2=Rosenfeld |first2=R. N.}}</ref> [[carbon trioxide]] (CO{{sub|3}}),<ref>{{cite journal |title=A theoretical study of the structure and properties of carbon trioxide |last1=Sabin |first1=J. R. |journal=[[Chemical Physics Letters]] |volume=11 |issue=5 |pages=593–597 |date=1971 |doi=10.1016/0009-2614(71)87010-0 |bibcode=1971CPL....11..593S |last2=Kim |first2=H.}}</ref><ref>{{cite journal |title=Carbon Trioxide: Its Production, Infrared Spectrum, and Structure Studied in a Matrix of Solid CO{{sub |2}} |journal=Journal of Chemical Physics|date=1966|volume=45|issue=12|pages=4469–4481|doi=10.1063/1.1727526|bibcode=1966JChPh..45.4469M |author=Moll N. G.|author2=Clutter D. R.|author3=Thompson W. E.}}</ref> [[cyclopentanepentone]] (C{{sub|5}}O{{sub|5}}),<ref name="Fatiadi-1963">{{cite journal |title=Cyclic Polyhydroxy Ketones. I. Oxidation Products of Hexahydroxybenzene (Benzenehexol) |journal=Journal of Research of the National Bureau of Standards Section A |volume=67A |issue=2 |date=1963 |pages=153–162 |url=http://nvl.nist.gov/pub/nistpubs/jres/067/2/V67.N02.A06.pdf |url-status=dead |access-date=2009-03-21 |doi=10.6028/jres.067A.015 |pmid=31580622 |pmc=6640573 |first1=Alexander J. |last1=Fatiadi |last2=Isbell |first2=Horace S. |last3=Sager |first3=William F. |archive-url=https://web.archive.org/web/20090325204012/http://nvl.nist.gov/pub/nistpubs/jres/067/2/V67.N02.A06.pdf |archive-date=2009-03-25}}</ref> [[cyclohexanehexone]] (C{{sub|6}}O{{sub|6}}),<ref name="Fatiadi-1963"/> and [[mellitic anhydride]] (C{{sub|12}}O{{sub|9}}). However, mellitic anhydride is the triple acyl anhydride of mellitic acid; moreover, it contains a benzene ring. Thus, many chemists consider it to be organic.

With reactive metals, such as [[tungsten]], carbon forms either [[carbide]]s (C{{sup|4−}}) or [[acetylide]]s ({{chem|C|2|2-}}) to form alloys with high melting points. These anions are also associated with methane and [[acetylene]], both very weak acids. With an electronegativity of 2.5,<ref>{{cite book |first=L. |last=Pauling |title=The Nature of the Chemical Bond |url=https://archive.org/details/natureofchemical00paul |url-access=registration |edition=3rd |publisher=Cornell University Press |location=Ithaca, NY |date=1960 |page=[https://archive.org/details/natureofchemical00paul/page/93 93] |isbn=978-0-8014-0333-0}}</ref> carbon prefers to form [[covalent bond]]s. A few carbides are covalent lattices, like [[carborundum]] (SiC), which resembles diamond. Nevertheless, even the most polar and salt-like of carbides are not completely ionic compounds.{{sfn|Greenwood|Earnshaw|1997|pages=297-301}}