text: The analogy applies to other shapes besides tetrahedral and octahedral geometries. The derivations used in octahedral geometry are valid for most other geometries. The exception is square-planar because square-planar complexes typically abide by the 16-electron rule. Assuming ligands act as two-electron donors the metal center in square-planar molecules is d. To relate an octahedral fragment, ML, where M has a d electron configuration to a square planar analogous fragment, the formula ML where M has a d electron configuration should be followed.
  Further examples of the isolobal analogy in various shapes and forms are shown in figure 8.