Step 1: Define oxidation number.
The oxidation number (or oxidation state) of an atom in a molecule or ion represents the number of electrons that the atom can donate or accept when forming a bond. In coordination compounds, the oxidation number of the central metal atom is determined by considering the charges of the ligands and the overall charge of the complex.
Step 2: Example.
In the complex \( [Fe(CN)_6]^{4-} \), the cyanide \(CN^-\) ligand has a charge of -1. Since there are six cyanide ions, the total charge contributed by the ligands is -6. For the overall complex to have a charge of -4, the oxidation state of iron (Fe) must be +2. Thus, the oxidation number of the central metal atom (Fe) is +2.
Step 3: Conclusion.
The oxidation number of the central metal atom is the charge it has in a given complex.
(i) Draw the diagram which indicates the splitting of d-orbitals in tetrahedral field.
(ii) Write any one limitation of valence bond theory.
(i)[Ni(CN)₄]²⁻ and [Ni(CO)(_4)] have different structures, but do not differ in their magnetic behaviour. Explain.
(ii) Write the formula of Tetraamineaquachloridocobalt(III)chloride.
(i) Write two postulates of Werner's coordination theory.
(ii) Draw the geometrical isomers of [(NH_3)_3(NO_2)_3] and give their structures.