Re: In which case can we explain a bonding using VBT?

It's hard to make much of this question, since there is no context or example.

However, I think we can answer it by pointing out that hybridization is valence-bond theory.

Valence-bond theory is the theory that, on a very simplistic level, discusses the overlap of atomic orbitals on neighboring atoms. Those orbitals may be hybridized (e.g. sp²) or unhybridized (e.g. a pure p orbital).

Hybridization theory was formulated by Pauling to allow atomic orbitals to point in the same direction as the known interatomic directions in e.g. methane. This facilitates thinking of methane in terms of a simple atomic- orbital overlap picture.

Hybrid orbitals are simply a different way of thinking of the atomic orbitals involved in bonding - and in fact hybrid orbitals can be used with perfect validity in molecular-orbital theory treatments, though this is seldom done.

Dan Berger