orthonym.validation.halido_twin

Note

Internal API. Names and behaviour may change between releases.

The twin of an additive organometallic name: its halide ligands spelled ‘chloro’, not ‘chlorido’.

Compounds with at least one metal-carbon single bond (the Blue Book) names a compound of a

Group 3-12 metal by its ligands cited in alphanumerical order, then the metal: ‘[Ti(CH3)Cl3] trichlorido(methanido)titanium, trichlorido(methyl)titanium’ (:39789). Definitions of terms (:39761): “The names of anionic ligands, whether organic or inorganic, end in ‘o’. If the anion name ends in ‘ate’, ‘ite’, or ‘ide’, the final letter ‘e’ is replaced by ‘o’, giving ‘ato’, ‘ito’, or ‘ido’”, and (:39767) “Because of a long established tradition, names for substituent groups as defined in Section can also be used as ligand names”.

OPSIN 2.9.0 rejects the ‘chlorido’ ligand word (‘trichlorido(methyl)titanium’ has no parse) and reads the long-established spelling of the same ligand, ‘trichloro(methyl)titanium’, to the sigma-bonded structure. The name used to ship with no read-back at all (the organometallic_additive carve-out), and the sample of the CO audit (2026-10-17) found no wrong name among 27; this twin is the check that makes that a measured fact instead of a trust in the producer.

The twin is the name with each ‘chlorido’, ‘bromido’, ‘fluorido’, ‘iodido’ spelled ‘chloro’, ‘bromo’, ‘fluoro’, ‘iodo’; ‘hydrido’ is a word OPSIN reads and stays. It is a rewrite of the tokens of the name, applied to the additive names of the transition-metal producer only: a name of the shape of namer._ORGANOMETALLIC_ADDITIVE_PIN_RE without a hapto, kappa or mu descriptor (a name with one has no spelling OPSIN reads, and ships as the deliberate eta-hapto carve-out). The standard InChIKey does not see the bonds of a metal, so the read-back of the twin checks the ligands and their number; the producer certifies the bonds (rules.organometallics._sigma_additive_ligands_certified).

The twin proves the structure and never the spelling: the producer owns the spelling.

orthonym.validation.halido_twin.HAPTO_DESCRIPTOR = re.compile('[ηκμ]')

a name with one has no spelling OPSIN reads (the gate keeps it as the deliberate carve-out organometallic_additive, namer._final_opsin_validity_gate); the one home of the pattern

Type:

a hapto, kappa or mu descriptor

orthonym.validation.halido_twin.halido_twin(name)

The ‘chloro’ spelling of an additive organometallic name with ‘chlorido’ ligands, or name itself when it is no such name. Pure and deterministic.