Carbon compounds

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Carbon compounds are defined as chemical substances containing carbon. [1] [2] More compounds of carbon exist than any other chemical element except for hydrogen. Organic carbon compounds are far more numerous than inorganic carbon compounds. In general bonds of carbon with other elements are covalent bonds. 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 rings. [3]

Contents

Allotropes of carbon

The known inorganic chemistry of the allotropes of carbon (diamond, graphite, and the fullerenes) blossomed with the discovery of buckminsterfullerene in 1985, as additional fullerenes and their various derivatives were discovered. One such class of derivatives is inclusion compounds, in which an ion is enclosed by the all-carbon shell of the fullerene. This inclusion is denoted by the "@"symbol in endohedral fullerenes. For example, an ion consisting of a lithium ion trapped within buckminsterfullerene would be denoted Li+@C60. 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 compounds.

Carbides

Carbides are binary compounds of carbon with an element that is less electronegative than it. The most important are Al4C3, B4C, CaC2, Fe3C, HfC, SiC, TaC, TiC, and WC.

MetalStructure of pure metalMetallic
radius (pm)
MC
metal atom packing
MC structureM2C
metal atom packing
M2C structureOther carbides
titanium hcp147ccprock salt
zirconium hcp160ccprock salt
hafnium hcp159ccprock salt
vanadium bcc 134ccprock salthcph/2V4C3
niobium bcc146ccprock salthcph/2Nb4C3
tantalum bcc146ccprock salthcph/2Ta4C3
chromium bcc128Cr23C6, Cr3C,
Cr7C3, Cr3C2
molybdenum bcc139hexagonalhcph/2Mo3C2
tungsten bcc139hexagonalhcph/2

Organic compounds

It was once thought that organic compounds could only be created by living organisms. Over time, however, scientists learned how to 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. [4] 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: COCl2, CSCl2, CS(NH2)2, CO(NH2)2. With carbon bonded to metals the field of organic chemistry crosses over into organometallic chemistry.


Carbon-oxygen compounds

There are many oxides of carbon (oxocarbons), of which the most common are carbon dioxide (CO2) and carbon monoxide (CO). Other less known oxides include carbon suboxide (C3O2) and mellitic anhydride (C12O9). [5] There are also numerous unstable or elusive oxides, such as dicarbon monoxide (C2O), oxalic anhydride (C2O4), and carbon trioxide (CO3).

There are several oxocarbon anions, negative ions that consist solely of oxygen and carbon. The most common are the carbonate (CO32−) and oxalate (C2O42−). The corresponding acids are the highly unstable carbonic acid (H2CO3) and the quite stable oxalic acid (H2C2O4), respectively. These anions can be partially deprotonated to give the bicarbonate (HCO3) and hydrogenoxalate (HC2O4). Other more exotic carbon–oxygen anions exist, such as acetylenedicarboxylate (O2C–C≡C–CO22−), mellitate (C12O96−), squarate (C4O42−), and rhodizonate (C6O62−). The anhydrides 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 Ag2CO3, BaCO3, CaCO3, CdCO3, Ce2(CO3)3, CoCO3, Cs2CO3, CuCO3, FeCO3, K2CO3, La2(CO3)3, Li2CO3, MgCO3, MnCO3, (NH4)2CO3, Na2CO3, NiCO3, PbCO3, SrCO3, and ZnCO3.

The most important bicarbonates include NH4HCO3, Ca(HCO3)2, KHCO3, and NaHCO3.

The most important oxalates include Ag2C2O4, BaC2O4, CaC2O4, Ce2(C2O4)3, K2C2O4, and Na2C2O4.

Carbonyls are coordination complexes between transition metals and carbonyl ligands. Metal carbonyls are complexes that are formed with the neutral ligand CO. These complexes are covalent. Here is a list of some carbonyls: Cr(CO)6, Co2(CO)8, Fe(CO)5, Mn2(CO)10, Mo(CO)6, Ni(CO)4, W(CO)6.

Carbon-sulfur compounds

Important inorganic carbon-sulfur compounds are the carbon sulfides carbon disulfide (CS2) and carbonyl sulfide (OCS). Carbon monosulfide (CS) unlike carbon monoxide is very unstable. Important compound classes are thiocarbonates, thiocarbamates, dithiocarbamates and trithiocarbonates.

CS-CRC-MW-dimensions-2D-Lewis.png Carbon-disulfide-2D-dimensions.png Carbonyl-sulfide-2D-dimensions.png
carbon monosulfide carbon disulfide carbonyl sulfide
Inorganic carbon-sulfur compounds

Carbon-nitrogen compounds

Small inorganic carbon – nitrogen compounds are cyanogen, hydrogen cyanide, cyanamide, isocyanic acid and cyanogen chloride.

composition Molar mass (g/mole) Boiling point °C Melting point °C
cyanogen (CN)2 Cyanogen 200.svg 52.03−21−28
hydrogen cyanide HCN Hydrogen-cyanide-2D.svg 27.0325–26−12 – -14
cyanamide CN2H2 Cyanamide.svg 42.04260 (decomp.)44
isocyanic acid HNCO Isocyansaure.svg 43.0323.5−86
cyanogen chloride CNCl Cyanogen-chloride.svg 61.4713−6
chlorosulfonyl isocyanate CNClO3S Chlorosulfonyl isocyanate.svg 141.53107−44
cyanuric chloride (NCCl)3 Cyanuric chloride.png 184.41192154
Inorganic carbon-nitrogen compounds

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 salts and complexes of the carbon-containing cyanide, cyanate, fulminate, thiocyanate and cyanamide 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 (CF4), carbon tetrachloride (CCl4), carbon tetrabromide (CBr4), carbon tetraiodide (CI4), and a large number of other carbon-halogen compounds.

Carboranes

A carborane is a cluster composed of boron and carbon atoms such as H2C2B10H10.

Alloys

There are hundreds of alloys that contain carbon. The most common of these alloys is steel, sometimes called "carbon steel" (see Category:Steels). All kinds of steel contain some amount of carbon, by definition, and all ferrous alloys 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: aluminum, chromium, magnesium, molybdenum, niobium, thorium, titanium, tungsten, uranium, vanadium, zinc, and zirconium. For example, many of these metals are smelted with coke, a form of carbon; and aluminum and magnesium are made in electrolytic cells with carbon electrodes. Some distribution of carbon into all of these metals is inevitable.

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<span class="mw-page-title-main">Cyanide</span> Any molecule with a cyano group (–C≡N)

In chemistry, a cyanide is a chemical compound that contains a C≡N functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.

<span class="mw-page-title-main">Inorganic chemistry</span> Field of chemistry

Inorganic chemistry deals with synthesis and behavior of inorganic and organometallic compounds. This field covers chemical compounds that are not carbon-based, which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the chemical industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels, and agriculture.

<span class="mw-page-title-main">Organic compound</span> Carbon-containing chemical compound

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In chemistry, azide is a linear, polyatomic anion with the formula N−3 and structure N=N+=N. It is the conjugate base of hydrazoic acid HN3. Organic azides are organic compounds with the formula RN3, containing the azide functional group. The dominant application of azides is as a propellant in air bags.

In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as inorganic chemistry.

An acidic oxide is an oxide that either produces an acidic solution upon addition to water, or acts as an acceptor of hydroxide ions effectively functioning as a Lewis acid. Acidic oxides will typically have a low pKa and may be inorganic or organic. A commonly encountered acidic oxide, carbon dioxide produces an acidic solution when dissolved.

<span class="mw-page-title-main">Thiocyanate</span> Ion (S=C=N, charge –1)

Thiocyanates are salts containing the thiocyanate anion [SCN]. [SCN] is the conjugate base of thiocyanic acid. Common salts include the colourless salts potassium thiocyanate and sodium thiocyanate. Mercury(II) thiocyanate was formerly used in pyrotechnics.

Pseudohalogens are polyatomic analogues of halogens, whose chemistry, resembling that of the true halogens, allows them to substitute for halogens in several classes of chemical compounds. Pseudohalogens occur in pseudohalogen molecules, inorganic molecules of the general forms PsPs or Ps–X, such as cyanogen; pseudohalide anions, such as cyanide ion; inorganic acids, such as hydrogen cyanide; as ligands in coordination complexes, such as ferricyanide; and as functional groups in organic molecules, such as the nitrile group. Well-known pseudohalogen functional groups include cyanide, cyanate, thiocyanate, and azide.

<span class="mw-page-title-main">Cyanate</span> Anion with formula OCN and charge –1

The cyanate ion is an anion with the chemical formula OCN. It is a resonance of three forms: [O−C≡N] (61%) ↔ [O=C=N] (30%) ↔ [O+≡C−N2−] (4%).

<span class="mw-page-title-main">Potassium cyanate</span> Chemical compound

Potassium cyanate is an inorganic compound with the formula KOCN. It is a colourless solid. It is used to prepare many other compounds including useful herbicide. Worldwide production of the potassium and sodium salts was 20,000 tons in 2006.

In chemical nomenclature, the IUPAC nomenclature of inorganic chemistry is a systematic method of naming inorganic chemical compounds, as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It is published in Nomenclature of Inorganic Chemistry. Ideally, every inorganic compound should have a name from which an unambiguous formula can be determined. There is also an IUPAC nomenclature of organic chemistry.

<span class="mw-page-title-main">Copper(I) cyanide</span> Chemical compound

Copper(I) cyanide is an inorganic compound with the formula CuCN. This off-white solid occurs in two polymorphs; impure samples can be green due to the presence of Cu(II) impurities. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of nitriles.

Cyanogen bromide is the inorganic compound with the formula (CN)Br or BrCN. It is a colorless solid that is widely used to modify biopolymers, fragment proteins and peptides, and synthesize other compounds. The compound is classified as a pseudohalogen.

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In chemistry, carbonylation refers to reactions that introduce carbon monoxide (CO) into organic and inorganic substrates. Carbon monoxide is abundantly available and conveniently reactive, so it is widely used as a reactant in industrial chemistry. The term carbonylation also refers to oxidation of protein side chains.

Zinc compounds are chemical compounds containing the element zinc which is a member of the group 12 of the periodic table. The oxidation state of zinc in most compounds is the group oxidation state of +2. Zinc may be classified as a post-transition main group element with zinc(II). Zinc compounds are noteworthy for their nondescript appearance and behavior: they are generally colorless, do not readily engage in redox reactions, and generally adopt symmetrical structures.

<span class="mw-page-title-main">Oxocarbon anion</span> Negatively-charged molecule made of carbon and oxygen

In chemistry, an oxocarbon anion is a negative ion consisting solely of carbon and oxygen atoms, and therefore having the general formula C
x
On
y
for some integers x, y, and n.

The carbonate oxalates are mixed anion compounds that contain both carbonate (CO3) and oxalate (C2O4) anions. Most compounds incorporate large trivalent metal ions, such as the rare earth elements. Some carbonate oxalate compounds of variable composition are formed by heating oxalates.

<span class="mw-page-title-main">Selenocyanate</span> Class of chemical compounds

A selenocyanate is an ion or chemical compound that contains the -SeCN group, which could be in the form of an anion, SeCN. Organic selenocyanates also exist.

References

  1. Organic Chemistry by Abraham William Simpson
  2. Encyclopedia of Inorganic Chemistry Bruce King Ed. Second Edition
  3. Advanced Inorganic Chemistry Cotton, F. Albert / Wilkinson, Geoffrey
  4. Chemistry Operations (December 15, 2003). "Carbon". Los Alamos National Laboratory. Retrieved 2007-11-21.
  5. It is an organic compound.