Organic Chemistry is a sub discipline within Chemistry, involving the scientific study of the structure, properties, composition, reactions, and preparation - by synthesis or by other means - of carbon-based compounds, hydrocarbons, and their derivatives. These compounds may contain any number of other elements, including hydrogen, nitrogen, oxygen, the halogens as well as phosphorus, silicon and sulphur. Organic compounds are structurally diverse. The range of application of organic compounds is enormous. They form the basis of or are important constituents of many products, including plastics, drugs, petrochemicals, food, explosives, and paints.