text: Walsh diagrams in conjunction with molecular orbital theory can also be used as a tool to predict reactivity.  By generating a Walsh Diagram and then determining the HOMO/LUMO of that molecule, it can be determined how the molecule is likely to react.  In the following example, the Lewis acidity of AH molecules such as BH and CH is predicted.
  Six electron AH molecules should have a planar conformation. It can be seen that the HOMO, 1e’, of planar AH is destabilized upon bending of the A-H bonds to form a pyramid shape, due to disruption of bonding. The LUMO, which is concentrated on one atomic center, is a good electron acceptor and explains the Lewis acid character of BH and CH.
  Walsh correlation diagrams can also be used to predict relative molecular orbital energy levels. The distortion of the hydrogen atoms from the planar CH to the tetrahedral CH-Nu causes a stabilization of the C-Nu bonding orbital, σ.