Werner’s theory was the pioneer to explain the bonding in coordinate complexes. According to his theory, there are two types of valences associated with central metal ions i.e. primary valency and secondary valency. But this theory was not able to predict the properties of coordinate complexes. VBT does have some advantages over Werner’s theory but still is having some significant drawbacks. Crystal field splitting theory and ligand field splitting theory got great success in depicting the properties of complexes with higher accuracy. CFST states that when ligands approach the isolated metal ion then the ligand’s field splits the degenerated d-orbitals of the isolated metal ion into the states of higher and lower energy with a forbidden energy gap in between.