Valence Bond Theory (VBT):
- VBT explains the bonding in coordination compounds by considering the hybridization of orbitals on the central metal atom or ion.
- The metal ion provides vacant orbitals to accommodate the lone pairs of electrons donated by ligands, forming coordinate covalent bonds.
- The geometry of the complex depends on the type of hybridization:
- \( sp^3 \): Tetrahedral
- \( dsp^2 \): Square planar
- \( d^2sp^3 \): Octahedral
Demerits of VBT:
1. Fails to explain the color of coordination compounds.
2. Cannot account for the magnetic properties of some complexes.
3. Does not provide a quantitative measure of bond strength or stability.
(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.