(i) Write down the IUPAC name of the following complex:
[Cr(en)3]Cl3
(ii) Write the formula for the following complex:
Potassium tri oxalato chromate(III)
(i) IUPAC name of the complex is tris(ethane-1,2-diamine)chromium(III)chlorate.
Explanation: en stands for ethane-1,2-diamine. en is a neutral ligand so it is named before the cationic ligand (prefix). Since it already has a numerical prefix (‘di’ in diamine), to indicate the no. of en ‘tris’ is used. The oxidation number of chromium inside the complex is +3.
(ii) Formula for the complex is K3[Cr(C2O4)3]
Explanation: Cation is always written first. Then other ligands are written in the reverse order inside square brackets i.e., chromium symbol is written first and then oxalate formula with the oxidation number of chromium as subscript.