Thursday 30 July 2015

Nomenclature of coordination compounds:
1) Orders of naming ions in coordination complexes :
The names of neutral coordination complexes are given without spaces and for ionic coordination complexes the cation is named first & then the anion separated by a space.

Here the coordination complex is neutral, so no spaces are necessary. The word ‘ mer' is used for expressing the geometry.

In the above examples, the cations sodium is named first and then separated by a space from the names of the anions
2) Naming the coordination sphere: ligands are named first & then the metal ion.

3) Names of the ligands: Negative ligands end in –o & the positive ligands end in –ium. The neutral ligands are named as such.

4) Order of naming the ligands: alphabetical order irrespective of their charge. ( IUPAC convention)
5) Numerical prefix to indicate the number of ligands:





Remember that you never have to indicate the number of cations and anions in the name of an ionic compound .
6) Ending of names:

7) Oxidation state of the central ion: Roman numerical (such as II, III, IV) at the end of metal part without any spacing.

8) Bridging group: ยต- is written as a prefix of the ligand name.


9) Point of attachment: if there is more than one atom for attachment with metal then the symbol of atom is written after the name of ligand.


10) Isomer:

Q. You can have a compound where both the cation and the anion are complex ions. Notice how the name of the metal differs even though they are the same metal ions. What's the name of that type of compound e.g. [Ag(NH3)2][Ag(CN)2] ?
Answer: diamminesilver(I) dicyanoargentate(I)
Q. Write the name of the following complexes:
1.    [CoCl3(NH3)3]
2.    [Co(ONO)3(NH3)3]
3.    [Fe(ox)2(H2O)2]

4.    Ag2[HgI4]

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