Page 19 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

G E N E R A L A I M S , F U N C T I O N S A N D M E T H O D S I R-1.6

Examples:
3. HNNH , h ydrazine-1,2-diide

4. MeNH , m ethanaminide

5. porphyrin-21,23-diide

(iii) Additive names of anions end in ‘ate’.

Example:
6. PS 4 , t etrasulfidophosphate(3 )
3

These rules now apply w hether t he anion is a r adical or not, leading to changes t o
Ref. 22 for additive names of certain radical anions. For e xample, HSSH * was named
bis(hydridosulfide)(S–S)( * 1 ) 22 but is here named bis(hydridosulfate)(S–S)( * 1 ).
There are also differences f rom Refs. 11 and 19 where some parent hydride-based anions
were missing locants and had a c harge number added. For example, in Ref. 19 one n ame f or

HNNH was hydrazide(2 ), whereas it is now hydrazine-1,2-diide.

IR-1.6.3 The element sequence of Table VI
In Nomenclature of Inorganic Chemistry, IUPAC Recommendations 1990 (Ref. 11), the
position of oxygen in certain element sequences was treated as an exception. Such
exceptions have been removed and the element sequence of Table VI is now strictly adhered
to. In particular, oxygen is treated as the electropositive component relative to any halogen
for constructing compositional names (Section IR-5.2) a nd corresponding formulae (Section
IR-4.4.3) for binary compounds. This results in, for example, the formula O 2 Cl and the name
dioxygen chloride rather than the formula ClO 2 and the name chlorine dioxide.
In Ref. 11, t he formulae for intermetallic compounds were also subject to an exceptional
rule although no guidance was given f or 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 t o m ake a s eparate prescription for either the formulae or the names of intermetallic
compounds. It is stressed, however, t hat the present recommendations allow some fl exibility
regarding formulae and compositional names of ternary, quaternary, etc. compounds. Several
ordering p rinciples are often equally acceptable (see Sections IR-4.4.2 and IR-4.4.3).
The element sequence of Table VI is also adhered to when o rdering central
atoms in polynuclear compounds for the purpose of constructing additive names (see
Section IR-1.6.6).

IR-1.6.4 Names of anionic ligands in (formal) c oordination entities

The rule n ow used, without exception, is that anion n ames ending in ‘ide’, ‘ite’ and ‘ate’,
respectively, are changed t o e nd in ‘ido’, ‘ito’ and ‘ato’, respectively, when modifying the
ligand name for use in additive nomenclature (Sections IR-7.1.3, and IR-9.2.2.3). This
entails several changes f rom Refs. 11 and 22.
Certain simple l igands have historically (and in Ref. 11) been represented in names by
abbreviated forms: fluoro, chloro, bromo, i odo, hydroxo, hydro, cyano, oxo, etc. Following

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