Halogens nomenclature

The lUPAC rules permit alkyl halides to be named m two different ways called func twnal class nomenclature and substitutive nomenclature In functional class nomencla ture the alkyl group and the halide (fluoride chloride bromide or iodide) are desig nated as separate words The alkyl group is named on the basis of its longest continuous chain beginning at the carbon to which the halogen is attached... 

Substitutive nomenclature of alkyl halides treats the halogen as a halo—(fluoro chloro bromo or lodo ) substituent on an alkane chain The carbon chain is numbered m the direction that gives the substituted carbon the lower number... 

Halogen Derivatives. Using substitutive nomenclature, names are formed by adding prefixes listed in Table 1.8 to the name of the parent compound. The prefix perhalo- implies the replacement of all hydrogen atoms by the particular halogen atoms. 

Haber, F., 357, 385 Hahn, O., 717 half-cell, 492 half-life (chemical), 543 half-life (radioactive), 712 half-reaction, 484 halide, nomenclature, 763 Hall, C., 598 Hall process, 598 haloakane, F36, 739, 756 nomenclature, 763 halogen, F20, 639... 

It is generally an arbitrary matter to decide where to apply substitutive nomenclature in these cases. Table 5.1 shows the elements to which both CNIC and CNOC approve the application. Table 5.2 gives the names of the corresponding mononuclear parent hydrides. The only additional elements to which substitutive nomenclature may sometimes be applied are the halogens, particularly iodine. 

His scheme of nomenclature for nitrogen compounds, and the names thio-, chloro-, etc, did become widespread, especially for sulfur and halogen compounds. 

Hydrocarbons, esters, etc., which have one or more hydrogen atoms replaced by a halogen atom are named so that the substituents have the lowest possible numbers. When multiple functions are present, they are numbered according to precedences established by IUPAC or CAS nomenclature rules. Both trivial and systematic nomenclatures are used. 

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