monochloro

Monochloro is a chemical naming prefix used in organic and inorganic nomenclature to indicate that a molecule contains exactly one chlorine substituent on its parent structure. The term combines mono- meaning one with chloro-, derived from chlorine. In systematic IUPAC naming, monochloro- is attached to the name of the parent compound to specify a single chlorine atom, with the position of the substituent indicated when necessary.

Examples include monochloroethane, indicating one chlorine on an ethane skeleton (CH3CH2Cl), and monochlorocyclohexane, with one chlorine on a cyclohexane ring (C6H11Cl). Monochloro derivatives of other parents occur as well, such as monochlorobenzene (a benzene ring with a single chlorine substituent). In everyday usage, many compounds with a single chlorine substituent are also simply named using the simpler chloro- prefix, but monochloro- appears in more formal or systematic naming.

Differences among chlorine-count prefixes are common: dichloro- for two substituents, trichloro- for three, and so on, with substituent positions specified as needed (for example, 1,2-dichloropropane). The term monochloro does not refer to a single chemical substance itself; rather, it is a conventional prefix used to describe the substitution pattern of a larger parent molecule.

See also: chlorination, organochlorine compounds, halogen naming conventions.

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