Carbon is involved in inorganic compounds as well as organic compounds. Generally speaking, organic compounds contain carbon and hydrogen. This is not a firm rule. H₂CO₃ would be regarded as inorganic, while CCl₄ would usually be regarded as organic.

Carbonates involve the carbonate ion, CO₃^2-. Many carbonate compounds are found on earth's surface. Marble, for example, contains large amounts of calcium carbonate.

Carbonates generally react with acids to produce carbon dioxide, CO₂. Aqueous solutions of CO₂ are acidic:

H₂O + CO₂ H⁺ + HCO₃^-

Carbides may involve carbon atoms bounds into network structures, such as in silicon carbide (SiC) and boron carbide (B₄C₃). Both of these materials are very hard, and serve as abrasives. Quite a different situation exists for calcium carbide, CaC₂. This substance can be thought of as the calcium salt of acetylene. When placed in water, solid calcium carbide reacts to produce acetylene gas.

CaC₂ + 2H₂O --> C₂H₂ + Ca(OH)₂

Many metal carbides are known, such as tungsten carbide, WN. Cementite, Fe₃C, is a very hard material. Steels containing Fe₃C are very hard.

See jmol: Tungsten Carbide