Parent hydride names

Cations can also be obtained by the formal addition of a hydron (hydron is the recommended name for the normal isotopic mixture of protons, deuterons and tritons, see p. 7) to a binary hydride. In such cases, a formalism of substitutive nomenclature is used the suffix -ium is added to the name, slightly modified, of the parent hydride. The selection of permitted hydride names and their usage are discussed in Section 4.5 on substitutive nomenclature. 

Anions obtained formally by loss of a hydron from a parent hydride (see Table 5.2 p. 99 for a list of parent hydride names) are conveniently named by the methods of substitutive nomenclature. 

The modified element name sila indicates replacement in the carbon skeleton, and similar treatment can be applied to other element names. The parent hydride names of Table 5.2 may all be adapted in this way and used in the same fashion as in the oxa-aza nomenclature of organic chemistry. In inorganic chemistry, a major use is in names of cyclic derivatives that have heteroelement atoms replacing carbon atoms in structures. It may be possible to name such species by Hantzsch-Widman procedures (see p. 77), and these should always be used when applicable. 

Introduction. This is a method of naming, commonly used for organic compounds, in which names are based on that of an individual parent hydride, usually ending in-ane. -ene or -yne. The hydride name is understood to signify a definite fixed population of hydrogen atoms attached to a skeletal structure. 

Generally, nomenclature systems require a root on which to construct the name. This root can be an element name (e.g. cobalt or silicon ) for use in additive nomenclature, or can be derived from an element name (e.g. sil from silicon , plumb from plumbum for lead) and elaborated to yield a parent hydride name (e.g. silane or plumbane ) for use in substitutive nomenclature. 

Substitutive nomenclature is recommended only for derivatives of the parent hydrides named in Table IR-6.1 (in Section IR-6.2.1), and derivatives of polynuclear hydrides containing only these elements (see Sections IR-6.2.2 to IR-6.2.4). The bonding numbers of the skeletal atoms are understood to be as in Table IR-6.1 (these bonding numbers, e.g. 4 for Si and 2 for Se, are termed standard bonding numbers). Other bonding numbers must be indicated by an appropriate designator (the X convention , see Section IR-6.2.2.2 and Section P-14.1 of Ref. 1). 

Constructing a substitutive name generally involves the replacement of hydrogen atoms in a parent structure with other atoms or atom groups. Related operations, often considered to be part of substitutive nomenclature, are skeletal replacement (Section IR-6.2.4.1) and functional replacement in oxoacid parents (Section IR-8.6). Note that some operations in parent hydride-based nomenclature are not substitutive operations (e.g. formation of cations and anions by addition of H+ and H, respectively, cf. Sections IR-6.4.1 and IR-6.4.5). Names formed by the modifications of parent hydride names described in those sections are still considered part of substitutive nomenclature. 

The compositional name hydrogen peroxide (cf. Chapter IR-5) is an alternative to dioxidane for H2O2 itself, but is not applicable as a parent hydride name in substitutive nomenclature. 

Multiplicative prefixes indicate the presence of two or more identical substituents if the substituents themselves are substituted, the prefixes bis , tris , tetrakis , etc. are used. In the case of a multiplicative prefix ending in a and a suffix starting with a vowel, the a is elided (see Example 2 below). The final e of a parent hydride name is elided in front of a suffix starting with a vowel (see Examples 1 and 5 below). 

The name of an ion formally derived by adding a hydron to a parent hydride is obtained by adding the suffix ium to the name of the parent hydride, with elision of a final e For polycations formed in this way, the suffixes diium , triiunT, etc., are used without elision of any final e on the parent hydride name. Any necessary locants are placed immediately preceding the suffix. Locants for added hydrons take precedence over locants for unsaturation, as in Example 8 below. 

Names of substituted derivatives of cations are formed from the modified parent hydride names (as described in IR-6.4.1 and IR-6.4.2) by adding appropriate substituent prefixes. When numbering derivatives of polynuclear parents, the locants for added hydrons or removed hydride ions take precedence over locants for substituents, as in Example 6 below. 

Names of substituted derivatives of anions are formed from parent hydride names modified as above (see Sections IR-6.4.4 and IR-6.4.5) by further adding appropriate prefixes for the substituents. When numbering the structure, the position where a hydron was removed or a hydride ion was added takes precedence over the positions with substituents, as in Example 4 below. In many cases, additive names are common and acceptable alternatives. 

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 ... 

If several of the above features [cationic moiety, anionic moiety, radical formed by removal of hydrogen atom(s)] are present in a molecule or ion, a rule is needed to decide in which order to cite the various modifications of the parent hydride name. 

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

A1H A1H, aluminium monohydride [A1H], -alumane (parent hydride name), hydridoaluminium A1H+, hydridoaluminium) 1+) ... 

CH4, methane (parent hydride name), tetrahydridocarbon CH4 +, methaniumyl, tetrahydridocarbon) 1 +) CH4, methanuidyl, tetrahydridocarbonate( 1—)e ... 

GeH4 GeH4, germane (parent hydride name), tetrahydridogermanium ... 

HC1 HC1, hydrogen chloride [HC1], chlorane (parent hydride name), chloridohydrogen HC1+, chloraniumyl, chloridohydrogen) 1 +) ... 

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