Page 157 - 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-9.1

Example:
1. Addition of ligands to a c entral atom:

Ni 2þ þ 6H 2 O [Ni(OH 2 ) 6 ] 2þ
Addition of ligand names to a c entral atom name:
hexaaquanickel(II)

This nomenclature then extends to more c omplicated structures where central atoms
(and their ligands) a re added together to form polynuclear species from mononuclear
building blocks. Complicated structures a re usually more easily named by treating them as
polynuclear species (see Section IR-9.2.5).

IR-9.1.2.10 Bridging ligands

In polynuclear species a l igand can also a ct as a b ridging group, by forming b onds to two
or more central atoms simultaneously. Bridging is indicated in names and formulae
by adding the symbol m as a p refix to the ligand formula or name (see Section IR-9.2.5.2).
Bridging ligands link central atoms together to produce c oordination entities h aving
more than one central atom. The number of central atoms joined into a s ingle coordination
entity by bridging ligands or direct bonds between central atoms is indicated by using the
terms dinuclear, trinuclear, tetranuclear, etc.
The bridging i ndex i s t he number of central atoms linked by a p articular bridging ligand
(see Section IR-9.2.5.2). Bridging can be through one atom or through a l onger array of atoms.

Example:

1. Cl Cl Cl

Al Al

Cl Cl Cl
[Al 2 Cl 4 (m-Cl) 2 ] o r [ Cl 2 Al(m-Cl) 2 AlCl 2 ]
2
2
di-m-chlorido-tetrachlorido-1k Cl,2k Cl-dialuminium
IR-9.1.2.11 Metal–metal bonds
Simple structures that contain a m etal–metal bond are readily described using additive
nomenclature (see Section IR-9.2.5.3), but complications arise for structures that involve
three or more central atoms. Species that contain such clusters of central atoms are treated
in Sections IR-9.2.5.6 and IR-9.2.5.7.

Examples:
1. [Br 4 ReReBr 4 ] 2þ
bis(tetrabromidorhenium)(Re—Re)(2þ)
2. 1 2
½ðOCÞ 5 ReCoðCOÞ 4
5
4
nonacarbonyl-lk C,2k C-rheniumcobalt(Re—Co)
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