The butyl group is a type of hydrocarbon group derived from butane, consisting of four carbon atoms and nine hydrogen atoms, represented as C4H9. It can exist in several structural forms, including n-butyl, isobutyl, sec-butyl, and tert-butyl, each differing in the arrangement of carbon atoms. Butyl groups are commonly found in various organic compounds and are important in the field of chemistry. They are often used in the production of plastics, rubber, and solvents, contributing to the properties and performance of these materials in industrial applications.