Substituent groups parent hydride names

Radicals and substituent groups derived from parent hydrides by removal of one or more hydrogen atoms are named by modifying the parent hydride name as follows ... 

There are two methods for constructing substituent group names from parent hydride names ... 

The groups attached to the principal chain are called substituents, and these may be simple or complex. Simple substituents are formed directly from parent hydrides when a simple substituent is itself substituted, it becomes complex as a consequence. Normal alkyl groups are simple substituents branched alkyl groups are complex substituents. However, as exceptions the names isopropyl, isobutyl, jec-butyl, tert-butyl, isopentyl, tert-pentyl and neopentyl are taken to refer to simple substituents. 

The preferred names are also obtained by applying the principles of substitutive nomenclature. Substituents, considered as replacing hydrogen atoms, are named using prefixes of the appropriate group names and are cited, if there is more than one, in alphabetical order before the name of the parent hydride, using parentheses and multiplicative prefixes as necessary. 

Chemical nomenclature deals with names of elements and their combinations. Whereas writing the symbol or the name of an element is straightforward, a choice of which element to write first in the formula and in the name has to be made as soon as an element is associated with one or more other elements to form, for example, a binary compound. The order of citation of elements in formulae and names is based upon the methods outlined below. Furthermore, groups of atoms, such as ions, ligands in coordination compounds and substituent groups in derivatives of parent hydrides, are ordered according to specified rules. 

Substitutive nomenclature is a system in which names are based on the names of parent hydrides, which define a standard population of hydrogen atoms attached to a skeletal structure. Names of derivatives of the parent hydrides are formed by citing prefixes or suffixes appropriate to the substituent groups (or substituents) replacing the hydrogen atoms (preceded by locants when required), joined without a break to the name of the unsubstituted parent hydride. 

Substituent groups (or substituents), considered as replacing hydrogen atoms in parent hydrides, are named using appropriate suffixes ( ol , thiol , peroxol , carboxylic acid , etc.) and prefixes ( hydroxy , phosphanyl , bromo , nitro , etc.). Substituent suffixes are ranked in Section P-43 of Ref. 1. Prefixes are extensively listed in Appendix 2 of Ref. 1. The case of substituents formed by removal of one or more hydrogen atoms from a parent hydride is explained briefly, with examples, in Section IR-6.4.7, and prefixes for many common inorganic substituents are included in Table IX. 

Some substituents are always cited as prefixes, most notably halogen atoms. Otherwise, the highest-ranking substituent (the principal characteristic group) is cited as a suffix and the rest of the substituents as prefixes. Except for hydro , prefixes are cited in alphabetical order before the name of the parent hydride, parentheses being used to avoid ambiguity. 

For polynuclear parent hydrides, numerical locants are often needed to specify the positions of substituent groups. If there are several equivalent numberings of the parent hydride skeletal atoms relative to the substituents after relevant mles from Section IR-6.2 have been applied, the numbering is chosen which leads to the lowest set of locants for the compound as a whole. If there is still a choice, lowest locants are assigned to the substituent cited first in the name. If all substitutable hydrogen atoms are replaced by the same substituent, the locants can be omitted, as in Example 20 below. 

Organometallic compounds of the elements of groups 13-16 are named according to the substitutive system of nomenclature, dealt with in Chapter IR-6. Thus, the name of the parent hydride (formed in accordance with the rules of Section IR-6.2) is modified by a prefix for each substituent replacing a hydrogen atom of the parent hydride. The prefix should be in appropriate substituent form (chloro, methyl, sulfanylidene, etc.) and not in ligand form (chlorido, methanido, sulfido, etc.). 

B > A1 > Ga > In > T1 > S > Se > Te > C Thus, for a compound containing both arsenic and lead, the parent hydride would be selected as AsH3, rather than PbH4, the lead atom then appearing in the name as a prefixed substituent, often with its own substituent groups. 

Ending resulting from the change of the ane ending in names of parent hydrides to form prefixes denoting bridging divalent substituent groups, e.g. diazano, —HNNH—. 

---