A name in which the replacement of an atom or a group of a parent structure by another atom or group is indicated by affixes attached to or inserted into the name of the parent structure. There are two main types of replacement names.
- Skeletal replacement name. A name in which the replacement of skeletal atoms and their associated hydrogen atoms is indicated by non-detachable prefixes. When carbon atoms are replaced by heteroatoms this method has been called 'a' nomenclature since the prefixes end in 'a'. Certain names in which the prefix '@T06347@-', 'seleno-' or 'telluro-' indicates replacement of a skeletal oxygen atom by a sulfur, selenium or tellurium atom, respectively, are also skeletal replacement names.
- Functional replacement name. A name containing prefixes or infixes which indicate the replacement of an oxygen atom or hydroxy group of a characteristic group, @F02556@ or class name by other atoms or groups.