Changes to previous IUPAC recommendations

Certain cations derived from parent hydrides were given names in Refs. 11 and 19 which appear to be substitutive but which do not follow the rules of substitutive nomenclature. For example, according to Refs. 11 and 19, N2H62+ may be named hydrazinium(2+). However, the ending ium in itself denotes addition of hydrogen(l-l-) and thus implies the charge. Consequently this cation is named hydrazinediium or diazanediium, with no charge number, both in Section IR-6.4.1 and in Ref. 21. 

When constructing systematic names for anions, consistency is achieved by adhering without exception to the following rules  

These rules now apply whether the anion is a radical or not, leading to changes to Ref. 22 for additive names of certain radical anions. For example, HSSH - was named bis(hydridosulhde)(5-5)( l—)22 but is here named bis(hydridosulfate)(5-5)( l—). 

There are also differences from Refs. 11 and 19 where some parent hydride-based anions were missing locants and had a charge number added. For example, in Ref. 19 one name for HNNH was hydrazide(2—), whereas it is now hydrazine-1,2-diide. 

In Ref. 11, the formulae for intermetallic compounds were also subject to an exceptional rule although no guidance was given for naming such compounds, and the term intermetallic compound was not defined. The problem is to define the term metal . Therefore, no attempt is now made to make a separate prescription for either the formulae or the names of intermetallic compounds. It is stressed, however, that the present recommendations allow some flexibility regarding formulae and compositional names of ternary, quaternary, etc. compounds. Several ordering principles are often equally acceptable (see Sections IR-4.4.2 and IR-4.4.3). 

---

IR-1.5.3.2 Compositional nomenclature IR-1.5.3.3 Substitutive nomenclature IR-1.5.3.4 Additive nomenclature IR-1.5.3.5 General naming procedures IR-1.6 Changes to previous IUPAC recommendations IR-1.6.1 Names of cations IR-1.6.2 Names of anions IR-1.6.3 The element sequence of Table VI IR-1.6.4 Names of anionic ligands in (formal) coordination entities IR-1.6.5 Formulae for (formal) coordination entities IR-1.6.6 Additive names of polynuclear entities IR-1.6.7 Names of inorganic acids IR-1.6.8 Addition compounds IR-1.6.9 Miscellaneous... 

---