C6H11

C6H11 is a chemical formula commonly encountered in organic chemistry. It denotes a family of hydrocarbon species containing six carbon atoms and eleven hydrogen atoms. Because a neutral, closed-shell hydrocarbon with this exact composition would have a noninteger degree of unsaturation, C6H11 most often appears as a reactive species such as the cyclohexyl radical (C6H11•) or as a cyclohexyl cation (C6H11+). In other words, C6H11 is not the formula of a single isolated neutral molecule, but a shorthand for several related fragments or ions.

Most familiar is the cyclohexyl radical, derived from cyclohexane by removal of one hydrogen. The cyclohexyl radical is a reactive intermediate in many reactions, including radical substitutions and polymerization processes. It also serves as a building block in the synthesis of cyclohexyl derivatives, such as cyclohexyl halides, esters, and ethers, where the cyclohexyl group is attached to various atoms or moieties.

Other carbon frameworks that would carry the same formula, such as branched or substituted radicals, can also be described by C6H11, illustrating that the formula alone does not specify a unique structure.

Generation and properties: Cyclohexyl radicals are typically generated in situ by homolytic cleavage of cyclohexyl halides, by hydrogen abstraction from cyclohexane, or by photolysis and radiolysis. They are highly reactive and short-lived under normal conditions. The cyclohexyl cation is a less stable, auxiliary species that may form transiently in acid-catalyzed processes or in rearrangement pathways.

See also: Cyclohexane, Cyclohexyl group, Radical (chemistry).