The compounds of carbon can be classified as organic and inorganic compounds.
Earlier the organic compounds were defined as those compounds which originated from living organisms but it is now possible to synthesize organic compounds in the laboratory, therefore, they are now defined as compounds of carbon.
The compounds of carbon, which are not organic compounds, are called inorganic compounds. Most of the inorganic compounds are obtained from various minerals. For example, limestone, marble and dolomite contain carbon as carbonates. The other inorganic compounds are carbides of metal (e.g. CaC2, calcium carbide), HCN, CS2 and oxides of carbon such as CO2 and CO.
The organic compounds are obtained from natural sources such as plants and animals, coal and petroleum. Plants and animals are sources of complex organic compounds such as carbohydrates, starch, oils, proteins, drugs. Coal gives us benzene, phenol, naphthalene whereas petroleum is source of petrol, diesel, kerosene, lubricating oils, wax and other compounds. In addition, a large variety of synthetic organic compounds exists and there number is increasing daily. Thus, the number of organic compounds as compared to the inorganic ones is very large.
The properties of organic and inorganic compounds are different from each other. Organic compounds are generally low melting solids or liquids. They dissolve in organic solvents such as benzene, alcohol, chloroform but are generally insoluble in water. The inorganic compounds are generally solids which have high melting and boiling points. They generally dissolve in water but are insoluble in organic solvents.