The shapes of molecules have fascinated chemists since van der Waals and le Bel
proposed the tetrahedral carbon atom in 1874 and ever since then chemists have
tried to develop models to explain these shapes. In this seminar I will review
the most important of these models: the localized orbital model, the VSEPR
model and the ligand close packing (LCP) model and compare their advantages and
disadvantages. Exceptions to the predictions of these models, particularly the
VSEPR model, have been the subject of much discussion and also the catalyst for
new experimental and theoretical studies, particularly in recent years on the
geometry of molecules of the transition metals.