alkyl group

In chemistry, an alkyl group is a hydrocarbon; typically an alkyl is a part of a larger molecule. The term is usually used loosely; there is no general formula for an alkyl group. In structural formulae, an alkyl group is represented with an R. Usually, alkyl groups resemble hydrocarbons, but with one less hydrogen atom. The species CH₃ is rarely encountered, but there are many methyl compounds. Lower Alkyl refers to an alkyl with one to six carbon atoms.