Page 171 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

C O O R D I N A T I O N C O M P O U N D S IR-9.2

Note, however, t hat the rules for formula w riting may be relaxed in various ways i n o rder
better to display particular features of the structures in question. Use is made o f t his
flexibility in many e xamples below.

Example:
1. [Rh 3 H 3 {P(OMe) 3 } 6 ]
trihydridohexakis(trimethyl p hosphite)trirhodium

If there is more t han one element designated as a c entral atom, these elements are ranked
according to the order in which they appear i n T able VI. The later an element appears in
the sequence of Table VI, the earlier it comes in the list of central atom symbols in the
formula as well as in the list of central atom names in the name o f t he complex.

Example:
2. [ReCo(CO) 9 ] n onacarbonylrheniumcobalt

For anionic species, t he ending ‘ ate’ and the charge number (see Section IR-5.4.2.2) are
added after the central atom list which is enclosed in parentheses if more than one element i s
involved.

Examples:

3. [Cr 2 O 7 ] 2 heptaoxidodichromate(2 )
4. [Re 2 Br 8 ] 2 octabromidodirhenate(2 )

5. 2−
S FeSPh
PhSFe S

PhSMo S
S MoSPh
[Mo 2 Fe 2 S 4 (SPh) 4 ] 2
tetrakis(benzenethiolato)tetrakis(sulfido)(dimolybdenumdiiron)ate(2 )

Although not e xtensively e xemplified here, it is worth noting that the formalism developed
below for polynuclear complexes is applicable also to (formal) complexes in which the
central atoms are not metals.

Example:
6. [PSO 7 ] 2 heptaoxido(phosphorussulfur)ate(2 )

A n umber of oxoacids and related species are given such names in Chapter IR-8 and
Table IX.

The symbol kappa, k, w as introduced, in Section IR-9.2.4.2, in order to specify the ligating
atoms in polyatomic ligands. T his u se also applies to such ligands when they appear in
polynuclear complexes. However, the symbol k then assumes a n ew function, namely that

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