Valence Bond Theory: The valence bond theory proposes that covalent bonding in coordination compounds occurs due to overlap of atomic orbitals. Valence elec...
Valence Bond Theory:
The valence bond theory proposes that covalent bonding in coordination compounds occurs due to overlap of atomic orbitals. Valence electrons, which are located in the outermost energy level, participate in bonding. These valence electrons form sigma bonds with the metal atoms, resulting in a crystalline structure. Valence bond theory also predicts the geometry of coordination compounds based on the hybridization of atomic orbitals. For example, octahedral geometry is observed when valence electrons form equivalent sigma bonds with metal atoms arranged in a regular octahedral pattern.
Crystal Field Theory (Octahedral):
The crystal field theory describes the electronic structure of coordination compounds based on the arrangement of atomic orbitals in a crystal lattice. Octahedral geometry is an example of a crystal field with octahedral symmetry. The octahedral field is constructed by combining orbitals of the metal atom. Valence orbitals of metal atoms interact with atomic orbitals of surrounding ligands to form hybrid orbitals. These hybrid orbitals then form sigma bonds with the metal atoms. The arrangement of orbitals in the crystal field creates an octahedral energy level structure. Valence electrons occupy the orbitals in this field, giving rise to the observed octahedral geometry.
These two theories provide complementary insights into the bonding and geometry of coordination compounds. Valence bond theory focuses on the overlapping of atomic orbitals and predicting the molecular geometry, while the crystal field theory focuses on the arrangement of atomic orbitals in a crystal lattice and the resulting energy level structure