ABSTRACT
Polyatomic Covalent Molecules 4.1 Introduction Once more than two atoms are present in a molecule, the problem of molecular shape arises. For example, an AB4 molecule might be a tetrahedron, a square plane, or some less symmetrical shape. Since the molecule in its ground state adopts the shape which minimizes the total energy, a complete bonding theory would produce the shape of the molecule as one of its results. Unfortunately, such high accuracy calculations are only possible for simple species with few electrons. Thus the shape, or at least the symmetry, has to be determined by experiment, and we then require of our bonding theory a description of the shape rather than a prediction.
