orthonym.rules.ion_locants

Note

Internal API. Names and behaviour may change between releases.

Where the suffix of an ion may leave out the locant of its charged atom.

Citation of locants (the Blue Book): “In preferred IUPAC names, if any locants are

essential for defining the structure of the parent structure or of a unit of structure as defined by its appropriate enclosing marks, then all locants must be cited for the parent structure or that structural unit.” A cationic or anionic suffix is cited at the position of its charge ,:41366;,:41559;,:40900); the licences that leave the locant out are (:2873) and the specific methods of (:41555).

orthonym.rules.ion_locants.cites_a_locant(name)

A neutral name that carries a digit numbers its own parent hydride: its indicated hydrogen, hydro prefixes, ring fusion or substituents. That numbering does not number the charged atom of the ion, so an ionic suffix glued to the name has no locant to cite.

orthonym.rules.ion_locants.ring_ylium_may_be_locant_free(mol)

Specific method (the Blue Book): a hydride removed “from a terminal atom of a saturated unbranched acyclic hydrocarbon, a saturated monocyclic hydrocarbon, or a mononuclear parent hydride belonging to Group 14” gives the name of the parent hydride with ‘ane’ replaced by ‘ylium’ (‘cyclobutylium (PIN)’); the examples of the same paragraph include ‘triphenylsilylium (PIN)’, so the Blue Book does not confine the method to a bare ring. The general method (:41559) cites the position of the centre (‘furan-2-ylium (PIN)’,:41571). mol is the whole cation. This producer glues ‘ylium’ to the neutral name and has no locant for a substituent, so it takes only the bare saturated monocycle and declines every other ring cation (route_charged returns no name for it; another producer then cites the centre, ‘1-methylcyclobutan-1-ylium’ at the best-effort tier). ASSUMED, follow-up: the specific-method PIN of a substituted saturated monocycle (‘1-methylcyclobutylium’).

orthonym.rules.ion_locants.name_neutral_ring_for_ion(ring_mol, ring_atoms, centre_locant_is_cited)

The name of the neutral ring that an ionic suffix is added to. When the suffix cites the locant of its centre, (the Blue Book, see above) cites every locant of the unit, so the licence that left out the locant of the only substituent of the ring is off (‘2-methyloxirane’, not ‘methyloxirane’, for ‘2-methyloxiran-2-ide’; ‘1-methylcyclohexane’ for ‘1-methylcyclohexan-1-ide’). Only then: a switch that turns off every licence of the scope also reaches the substituents, which are units of their own.