Parent Hydrides

R-2.5 Substituent Prefix Names Derived from Parent Hydrides

The presence of one or more free valence(s) derived from the loss of one or more hydrogen atoms from a parent hydride is denoted by suffixes such as "-yl", "-diyl", "-ylidene", "-triyl", "-ylidyne".

Monovalent Divalent Trivalent Tetravalent etc.
-yl -diyl -triyl -tetrayl
-ylidene -ylidyne -ylylidyne etc.
-ylylidene -diylidene
Note: In these recommendations, the suffixes "-ylidene" and "-ylidyne" are used only to indicate the attachment of a substituent to a parent hydride or parent substituent by a double or triple bond, respectively.

These suffixes are used according to two methods as follows:

(a) The suffixes "-yl", "-ylidene", and "-ylidyne" replace the ending "-ane" of the parent hydride name. The atom with the free valence terminates the chain and always has the locant "1", which is omitted from the name. This method is recommended only for saturated acyclic and monocyclic hydrocarbon substituent groups and for the mononuclear parent hydrides of silicon, germanium, tin, lead, and boron.

(b) More general method. Any of these suffixes may be added to the name of the parent hydride with elision of a terminal "e", if present, before suffixes beginning with "y". The atoms with free valences are given numbers as low as is consistent with any established numbering of the parent hydride; except for the suffix "-ylidyne", the locant number "1" must always be cited.

Examples to R-2.5

Isopropylidene (when unsubstituted)

The contracted names adamantyl, naphthyl, anthryl, phenanthryl (R-9.1, Table 22) and furyl, pyridyl, isoquinolyl, quinolyl, piperidyl (R-9.1, Table 25) are retained. The trivial names vinyl, allyl, and phenyl (R-9.1, Table 19(b)) and thienyl, furfuryl, and thenyl (see R-9.1, Table 25) are retained for use with no limitation on substitution; other trivial names are retained but only with limited or no substitution (see R-9.1, Table 19(b)).

See Also:
R-2.0 Introduction
R-2.1 Mononuclear Hydrides
R-2.2 Monocyclic Hydrides
R-2.3 Monocyclic Hydrides
R-2.4 Polycyclic Parent Hydrides

This HTML reproduction is as close as possible to the published version [see IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds (Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC]. If you need to cite these rules please quote this reference as their source.

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