Question

Write the formula for Trioxalato cobaltate(III)ion.

Answer 1

Hint: As per IUPAC while writing the name for a coordination complex first we have to see whether the name of the complex contains the oxidation number of the metal in brackets. Later we have to find the anion part and cationic part of the coordination complex.

Complete answer:
- In the question it is asked to write the formula of the given complex Trioxalato cobaltate(III)ion.
- From the IUPAC name the metal which is present in the inorganic complex is cobalt.
- From the given IUPAC name we can find that the oxidation state of the cobalt is +3.
- The name Trioxalato means there are three oxalate ligands which are present in the given complex.
- In the name the name of the metal is written as cobaltate means the total complex is an anionic part.
- We can represent oxalate ligands in the form of ${{C}_{2}}{{O}_{4}}$ .
- The oxalate is a bidentate ligand means it is going to donate two electrons to cobalt metal in the coordination complex.
- Means three oxalate ligands are going to donate six electrons.
- Therefore we can write the formula of Trioxalato cobaltate(III)ion as ${{[Co({{C}_{2}}{{O}_{4}})]}^{3-}}$ .

Note:
Without finding the oxidation state of the metal in the coordination complex it is very difficult to write the chemical formula of the inorganic complex. We should find the cation and anion parts of the complex to write the chemical formula in a better way.