What are the limitations of VB theory?

Explanation

Eventhough VBT explain many of the observed properties of complexs. It stil has following limitations.
(i) It does not explain the colour of the complex.
(ii) It considers only the spin only magnetic moments and does not consider the other components of magnetic moments
(iii) It does not provide a quantitative explanation as to why certain complexes are linner orbital complexes and the others are outer orbital complexs and the others are outer orbital complexes for the same metal For example, ` [Fe(CN)_6]^(4-) ` is diamagnetic (low spin ) whereas ` [FeF_6]^(4-) ` is paramagnetic (high spin)