In chemistry, a<unk>  is a compound of carbon with a more  electronegative element.<unk> s are important industrially: for example, calcium<unk>  is a feedstock for the chemical industry and iron<unk> , Fe3C (cementite), is formed in steels to improve their properties.
Many<unk> s can be generally classified by chemical bonding type as follows:
salt-like ionic compounds
covalent compounds
interstitial compounds
"intermediate" transition metal<unk> s (a group of<unk> s that in bonding terms sit between the salt-like and interstitial<unk> s).
In addition to the<unk> s there are other groups of binary carbon compounds, i.e.
graphite intercalation compounds
alkali metal fullerides
endohedral fullerenes, where the metal atom is encapsulated inside a fullerene molecule
metallacarbohedrenes(met-cars) which are cluster compounds containing C2 units.
Carbide
Carbonyl
Acyl
Oxamyl
Acid
Acetyl
Halide
Hydrocarbon