Editing Carbon compounds

{{short description|Chemical substances containing carbon}}
{{More citations needed|date=December 2022}}
'''Carbon compounds''' are [[chemical substances]] containing [[carbon]].<ref>''Organic Chemistry'' by Abraham William Simpson</ref><ref>''Encyclopedia of Inorganic Chemistry'' Bruce King Ed. Second Edition</ref> More [[chemical compound|compound]]s of carbon exist than any other [[chemical element]] except for [[hydrogen]]. [[Organic compound|Organic]] carbon [[chemical compound|compound]]s are far more numerous than [[inorganic compound|inorganic]] carbon compounds. In general [[chemical bond|bonds]] of carbon with other [[chemical element|element]]s are [[covalent bond]]s. Carbon is [[tetravalent]] but carbon [[free radicals]] and [[carbenes]] occur as short-lived intermediates. Ions of carbon are [[carbocations]] and [[carbanions]] are also short-lived. An important carbon property is [[catenation]] as the ability to form long carbon chains and [[carbon ring|ring]]s.<ref>''Advanced Inorganic Chemistry'' Cotton, F. Albert / Wilkinson, Geoffrey</ref>

==Allotropes of carbon==
{{Main|Allotropes of carbon}}
The known [[inorganic chemistry]] of the [[allotropy|allotrope]]s of carbon ([[diamond]], [[graphite]], and the [[fullerene]]s) blossomed with the discovery of [[buckminsterfullerene]] in 1985, as additional fullerenes and their various derivatives were discovered. One such class of derivatives is [[inclusion compound]]s, in which an ion is enclosed by the all-carbon shell of the fullerene. This inclusion is denoted by the "@"symbol in [[endohedral fullerene]]s. For example, an ion consisting of a lithium ion trapped within buckminsterfullerene would be denoted Li<sup>+</sup>@C<sub>60</sub>. As with any other ionic compound, this complex ion could in principle pair with a [[counterion]] to form a salt. Other elements are also incorporated in so-called [[graphite intercalation compound]]s.

==Carbides==
[[Carbide]]s are [[binary compound]]s of carbon with an element that is less [[electronegative]] than it. The most important are
[[Aluminium carbide|Al<sub>4</sub>C<sub>3</sub>]],
[[Boron carbide|B<sub>4</sub>C]],
[[Calcium carbide|CaC<sub>2</sub>]],
[[Iron carbide|Fe<sub>3</sub>C]],
[[Hafnium(IV) carbide|HfC]],
[[Silicon carbide|SiC]],
[[Tantalum carbide|TaC]],
[[Titanium carbide|TiC]], and
[[Tungsten carbide|WC]].
{{table alignment}}
{| class="wikitable col1left" style="text-align:center"
! Metal
! Structure of<br>pure metal
! Metallic <br />radius<br>(pm)
! MC <br />metal atom<br>packing
! MC structure
! M<sub>2</sub>C <br />metal atom<br>packing
! M<sub>2</sub>C structure
! Other carbides
|-
| [[titanium]]
| rowspan=3|[[close-packing of equal spheres|HCP]]<br>(hexagonal<br>close-packed)
| 147
| rowspan=6|[[cubic crystal system|FCC]]
| rowspan=6|rock salt
| colspan=3 rowspan=3 style="background:#aa8888;"|
|-
| [[zirconium]]
| 160
|-
| [[hafnium]]
| 159
|-
| [[vanadium]]
| rowspan=6|[[Cubic crystal system|BCC]]<br>(body-centred<br>cubic)
| 134
| rowspan=5|HCP
| rowspan=5|h/2<br>{{clarify|date=April 2025}}
| V<sub>4</sub>C<sub>3</sub>
|-
| [[niobium]]
| 146
| Nb<sub>4</sub>C<sub>3</sub>
|-
| [[tantalum]]
| 146
| Ta<sub>4</sub>C<sub>3</sub>
|-
| [[molybdenum]]
| 139
|
| hexagonal
| Mo<sub>3</sub>C<sub>2</sub>
|-
| [[tungsten]]
| 139
|
| hexagonal
| 
|-
| [[chromium]]
| 128
|colspan=4 style="background:#aa8888;"|
|Cr<sub>23</sub>C<sub>6</sub>, Cr<sub>3</sub>C, Cr<sub>7</sub>C<sub>3</sub>, Cr<sub>3</sub>C<sub>2</sub>
|}

==Organic compounds==
{{Main|Organic compound}}
It was once thought that [[organic compound]]s could only be created by living organisms. Over time, however, scientists learned how to [[Wöhler synthesis|synthesize organic compounds in the lab]]. The number of organic compounds is immense and the known number of defined compounds is close to 10 million.<ref name=lanl>{{cite web|author=Chemistry Operations|date=December 15, 2003|url=http://periodic.lanl.gov/6.shtml|title=Carbon|publisher=Los Alamos National Laboratory|access-date=2007-11-21}}</ref> However, an indefinitely large number of such compounds is theoretically possible. 
By definition, an organic compound must contain at least one atom of carbon, but this criterion is not generally regarded as sufficient. Indeed, the distinction between organic and inorganic compounds is ultimately a matter of convention, and there are several compounds that have been classified either way, such as:
[[Phosgene|COCl<sub>2</sub>]],
[[Thiophosgene|CSCl<sub>2</sub>]],
[[Thiourea|CS(NH<sub>2</sub>)<sub>2</sub>]],
[[Urea|CO(NH<sub>2</sub>)<sub>2</sub>]].
With carbon bonded to metals the field of organic chemistry crosses over into [[organometallic chemistry]].

===Carbon-oxygen compounds===
There are many [[oxide]]s of carbon ([[oxocarbon]]s), of which the most common are [[carbon dioxide]] (CO<sub>2</sub>) and [[carbon monoxide]] (CO). Other less known oxides include [[carbon suboxide]] (C<sub>3</sub>O<sub>2</sub>) and [[mellitic anhydride]] (C<sub>12</sub>O<sub>9</sub>).<ref>It is an organic compound.</ref> There are also numerous unstable or elusive oxides, such as [[dicarbon monoxide]] (C<sub>2</sub>O), [[oxalic anhydride]] (C<sub>2</sub>O<sub>4</sub>), and [[carbon trioxide]] (CO<sub>3</sub>).

There are several [[oxocarbon anion]]s, negative ions that consist solely of oxygen and carbon. The most common are the [[carbonate]] (CO<sub>3</sub><sup>2−</sup>) and [[oxalate]] (C<sub>2</sub>O<sub>4</sub><sup>2−</sup>).  The corresponding acids are the highly unstable [[carbonic acid]] (H<sub>2</sub>CO<sub>3</sub>) and the quite stable [[oxalic acid]] (H<sub>2</sub>C<sub>2</sub>O<sub>4</sub>), respectively.  These anions can be partially deprotonated to give the [[bicarbonate]] (HCO<sub>3</sub><sup>−</sup>) and [[hydrogenoxalate]]  (HC<sub>2</sub>O<sub>4</sub><sup>−</sup>).  Other more exotic carbon–oxygen anions exist, such as [[acetylenedicarboxylic acid|acetylenedicarboxylate]] (O<sub>2</sub>C–C≡C–CO<sub>2</sub><sup>2−</sup>), [[mellitic acid|mellitate]] (C<sub>12</sub>O<sub>9</sub><sup>6−</sup>), [[squaric acid|squarate]] (C<sub>4</sub>O<sub>4</sub><sup>2−</sup>), and [[rhodizonic acid|rhodizonate]] (C<sub>6</sub>O<sub>6</sub><sup>2−</sup>).  The [[anhydride]]s of some of these acids are oxides of carbon; carbon dioxide, for instance, can be seen as the anhydride of carbonic acid.

Some important carbonates are
[[Silver carbonate|Ag<sub>2</sub>CO<sub>3</sub>]],
[[Barium carbonate|BaCO<sub>3</sub>]],
[[Calcium carbonate|CaCO<sub>3</sub>]],
[[Cadmium carbonate|CdCO<sub>3</sub>]],
[[Cerium(III) carbonate|Ce<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub>]],
[[Cobalt(II) carbonate|CoCO<sub>3</sub>]],
[[Caesium carbonate|Cs<sub>2</sub>CO<sub>3</sub>]],
[[Copper(II) carbonate|CuCO<sub>3</sub>]],
[[Iron(II) carbonate|FeCO<sub>3</sub>]],
[[Potassium carbonate|K<sub>2</sub>CO<sub>3</sub>]],
[[Lanthanum carbonate|La<sub>2</sub>(CO<sub>3</sub>)<sub>3</sub>]],
[[Lithium carbonate|Li<sub>2</sub>CO<sub>3</sub>]],
[[Magnesium carbonate|MgCO<sub>3</sub>]],
[[Manganese(II) carbonate|MnCO<sub>3</sub>]],
[[Ammonium carbonate|(NH<sub>4</sub>)<sub>2</sub>CO<sub>3</sub>]],
[[Sodium carbonate|Na<sub>2</sub>CO<sub>3</sub>]],
[[Nickel(II) carbonate|NiCO<sub>3</sub>]],
[[Lead(II) carbonate|PbCO<sub>3</sub>]],
[[Strontium carbonate|SrCO<sub>3</sub>]], and
[[Zinc carbonate|ZnCO<sub>3</sub>]].

The most important bicarbonates include 
[[Ammonium bicarbonate|NH<sub>4</sub>HCO<sub>3</sub>]],
[[Calcium bicarbonate|Ca(HCO<sub>3</sub>)<sub>2</sub>]],
[[Potassium bicarbonate|KHCO<sub>3</sub>]], and
[[Sodium bicarbonate|NaHCO<sub>3</sub>]].

The most important oxalates include
[[Silver oxalate|Ag<sub>2</sub>C<sub>2</sub>O<sub>4</sub>]],
[[Barium oxalate|BaC<sub>2</sub>O<sub>4</sub>]],
[[Calcium oxalate|CaC<sub>2</sub>O<sub>4</sub>]], 
[[Cerium oxalate|Ce<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub>]],
[[Potassium oxalate|K<sub>2</sub>C<sub>2</sub>O<sub>4</sub>]], and
[[Disodium oxalate|Na<sub>2</sub>C<sub>2</sub>O<sub>4</sub>]].

[[Carbonyl]]s are coordination complexes between transition metals and [[carbonyl]] ligands. [[Metal carbonyl]]s are complexes that are formed with the neutral ligand CO. These complexes are covalent. Here is a list of some carbonyls:
[[Chromium carbonyl|Cr(CO)<sub>6</sub>]],
[[Cobalt carbonyl|Co<sub>2</sub>(CO)<sub>8</sub>]],
[[Iron pentacarbonyl|Fe(CO)<sub>5</sub>]],
[[Manganese carbonyl|Mn<sub>2</sub>(CO)<sub>10</sub>]],
[[Molybdenum carbonyl|Mo(CO)<sub>6</sub>]],
[[Nickel carbonyl|Ni(CO)<sub>4</sub>]],
[[Tungsten carbonyl|W(CO)<sub>6</sub>]].

===Carbon-sulfur compounds===
Important inorganic [[carbon]]-[[sulfur]] compounds are the carbon sulfides [[carbon disulfide]] (CS<sub>2</sub>) and [[carbonyl sulfide]] (OCS). [[Carbon monosulfide]] (CS) unlike [[carbon monoxide]] is very unstable. Important compound classes are [[thiocarbonate]]s, [[thiocarbamates]], [[dithiocarbamate]]s and [[trithiocarbonate]]s. 
{| class="wikitable" style="text-align:center;"
||[[File:CS-CRC-MW-dimensions-2D-Lewis.png|80px]]
||[[File:Carbon-disulfide-2D-dimensions.svg|100px]]
||[[File:Carbonyl-sulfide-2D-dimensions.png|100px]]
|-
|| [[carbon monosulfide]]
|| [[carbon disulfide]]
|| [[carbonyl sulfide]]
|-
|Colspan=100%|'''Inorganic carbon-sulfur compounds'''
|}

===Carbon-nitrogen compounds===
Small inorganic carbon–nitrogen compounds are [[cyanogen]], [[hydrogen cyanide]], [[cyanamide]], [[isocyanic acid]] and [[cyanogen chloride]].
{|align="center"  class="wikitable"
|+style="background: #ccccff;"| Inorganic carbon-nitrogen compounds
!Name!!Formula!!Structure!!|[[Molar mass]]<br>(g/mole)!![[Boiling point]]<br>°C!![[Melting point]]<br>°C
|-
|[[cyanogen]]||(CN)<sub>2</sub>||[[File:Cyanogen 200.svg|100px|Cyanogen]]||52.03||−21||−28
|-
|[[hydrogen cyanide]]||HCN||[[File:Hydrogen-cyanide-2D.svg|100px|Hydrogen-cyanide]]||27.03||25–26|| −12 to −14
|-
|[[cyanamide]] ||CN<sub>2</sub>H<sub>2</sub>||[[File:Cyanamide.svg|200px|Cyanamide]]||42.04||260 (decomp.)||44
|-
|[[isocyanic acid]]||HNCO||[[File:Isocyansäure.svg|100px|isocyanic acid]]||43.03||23.5||−86
|-
|[[cyanogen chloride]]||CNCl||[[File:Cyanogen-chloride.svg|100px|cyanogen chloride]]||61.47||13||−6
|-
|[[chlorosulfonyl isocyanate]]||CNClO<sub>3</sub>S||[[File:Chlorosulfonyl isocyanate.svg|100px|Chlorosulfonyl isocyanate]]||141.53||107||−44
|-
|[[cyanuric chloride]]||(NCCl)<sub>3</sub>||[[File:Cyanuric chloride.png|100px|cyanuric chloride]]||184.41||192|| 154
|}

[[Paracyanogen]] is the [[polymerization]] product of cyanogen. [[Cyanuric chloride]] is the trimer of cyanogen chloride and [[2-cyanoguanidine]] is the dimer of cyanamide.

Other types of inorganic compounds include the inorganic [[Salt (chemistry)|salt]]s and [[complex (chemistry)|complexes]] of the carbon-containing [[cyanide]], [[cyanate]], [[fulminate]], [[thiocyanate]] and [[cyanamide]] [[polyatomic ion|ions]]. Examples of cyanides are [[copper cyanide]] (CuCN) and [[potassium cyanide]] (KCN), examples of cyanates are [[potassium cyanate]] (KNCO) and [[silver cyanate]] (AgNCO), examples of fulminates are [[silver fulminate]] (AgOCN) and [[mercury fulminate]] (HgOCN) and an example of a thiocyanate is [[potassium thiocyanate]] (KSCN).

==Carbon halides==
The common carbon halides are [[carbon tetrafluoride]] (CF<sub>4</sub>), [[carbon tetrachloride]] (CCl<sub>4</sub>), [[carbon tetrabromide]] (CBr<sub>4</sub>), [[carbon tetraiodide]] (CI<sub>4</sub>), and a large number of other carbon-[[halogen]] compounds.

==Carboranes==
A [[carborane]] is a cluster composed of boron and carbon atoms such as H<sub>2</sub>C<sub>2</sub>B<sub>10</sub>H<sub>10</sub>.

==Alloys==
There are [[list of alloys|hundreds of alloys]] that contain carbon. The most common of these [[alloy]]s is [[steel]], sometimes called "[[carbon steel]]" (see [[:Category:Steels]]). All kinds of steel contain some amount of carbon, by definition, and all [[alloy|ferrous alloy]]s contain some carbon.

Some other common alloys that are based on [[iron]] and [[carbon]] include [[anthracite iron]], [[cast iron]], [[pig iron]], and [[wrought iron]].

In more technical uses, there are also [[spiegeleisen]], an alloy of iron, [[manganese]], and carbon; and [[stellite]], an alloy of [[cobalt]], [[chromium]], [[tungsten]], and carbon.

Whether it was placed there deliberately or not, some traces of carbon is also found in these common metals and their alloys: [[aluminium]], [[chromium]], [[magnesium]], [[molybdenum]], [[niobium]], [[thorium]], [[titanium]], tungsten, [[uranium]], [[vanadium]], [[zinc]], and [[zirconium]]. For example, many of these metals are smelted with [[coke (fuel)|coke]], a form of carbon; and aluminium and magnesium are made in [[electrolytic cell]]s with carbon electrodes. Some distribution of carbon into all of these metals is inevitable.

==References==
{{Reflist}}

{{carbon compounds}}
{{ChemicalBondsToCarbon}}
{{Chemical compounds by element}}

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{{DEFAULTSORT:Compounds Of Carbon}}
[[Category:Inorganic chemistry]]
[[Category:Carbon compounds|C]]
[[category:Chemical compounds by element|C]]
[[Category:Carbon]]