The document outlines the IUPAC nomenclature system for coordination compounds, detailing various naming conventions for cations, anions, and ligands. It explains the order of naming components, the significance of ligand charges, and how to indicate the number of ligands using prefixes. Additionally, it addresses the oxidation states of metal ions and the use of bridging indices when ligands are shared between multiple metal centers.

1. IUPAC System of Nomenclature
for
Coordination Compounds
Dr. Mithil Fal Desai
Shree Mallikarjun and Shri Chetan Manju
Desai College Canacona Goa

2. System of Nomenclature for
Inorganic Compounds
1. Binary type nomenclature
NaCl -sodium chloride
2. Coordinative nomenclature
[Co(NO2)3(NH3)3] –triamminetrinitrocobalt(?)
3. Substitutive type nomenclature
PCl3 -trichlorophosphane

3. Nature of coordination compound
Cationic [Co(H2O)6]Cl2  hexaaquacobalt(II) chloride
Anionic K3[Fe(CN)6]  potassium
hexacynoferrate(III)
Neutral [Ni(CO)4] 
tetracarbonylnickel(0)

4. 1. The order of naming of cation and anion.
In ionic coordination complexes, the cationic part is named first and
then the anion.
[Co(H2O)6]Cl2  hexaaquacobalt(II) chloride

5. 2. Naming the coordination compound
The name of the ligands are written before the central metal ion.
[Co(H2O)6]Cl2  hexaaquacobalt(II)
chloride
K3[Fe(CN)6]  potassium
hexacynoiron(III)

6. 3. Naming of the ligands based on their charge.
• Names of negative ligands end in –o
Br-
- bromo/bromido
• Names of positive ligands end in –ium
NO+
-nitrosonium
• Neutral ligands are retain their original name
CO –carbonyl
NH3?

7. Ligand Formula Name Denticity
ammonia NH3 ammine 1
water H2O aqua 1
carbon monoxide CO carbonyl 1
pyridine pyr pyridine 1
bipyridine bipy bipyridine 2
ethylenediamine en ethylenediamine 2
Common neutral ligands

8. Charge Ligand Formula Name
-1
iodide I
iodo
bromide Br
bromido/bromo
chloride Cl
chlorido/chloro
cyanide CN
cyanido/cyno
fluoride F
fluorido/fluoro
hydroxide OH
hydroxido/hydroxo
nitrite NO2

nitrito
hydride H
hydrido
azide N3

azido/azo
thio HS-
mercapto
Common monodentate ligands

9. Charge Ligand Formula Name
-2
carbonate CO3
2
carbonato
oxalate C2O4
2
oxolato
Common bidentate ligands

10. The prefixes di-,tri-,tetra-,penta-,hexa-, etc. specify the number of
ligands.
[Co(H2O)6]Cl2 hexaaquacobalt(II) chloride
Note: The complex having two, three, four organic ligands are
represented by prefixes such as bis, tris, tetrakis, respectively.
[Cr(C6H6)2] -bis(benzene)chromium(0)
[Cr(en)3]Cl3 –tris(ethylenediamine)chromium(III) chloride
4. The numerical prefixes are used to represent the
number of ligands.

11. Ligands are named in their alphabetical order.
[Co(Cl)(CN)(NO2)(NH3)3]
triamminechlorocynonitritocobalt(III)
5. The order of naming ligands.

12. 6. Ending of the metal atom/ion name.
The positive ion and neutral metal complex have no special ending but
anionic complexes, the name of central metal atom ends in -ate.
K3[Fe(CN)6]  potassium hexacynoferrate(III)
[Fe(H2O)6]Cl2  hexaaquairon(II) chloride

13. The oxidation state of the central metal atom/ion is
written at end of metal/ion as
___nickel(0), or ____ferrate(II)
[Co(H2O)6]Cl2 hexaaquacobalt(II) chloride
[Cr(C6H6)2] -bis(benzene)chromium(0)
7. Oxidation state of the central ion

14. The Greek letter µn- is written before the names of ligands
which shared between two or more metal ions. Where ‘n’
(bridging index) is number of coordinating metal ceters
attached to the ligand.
[(CO)3 Fe(CO)3 Fe(CO)3] –tri-µ-carbonyl-bis(tricarbonyliron(0))
Note: If ‘n’ is 2 the bridging index is not normally indicated.
8. The bridging groups