Aromaticity in metallacyclobutadienes from the perspective of the valence bond theory

The valence bond method has been implemented for the study of π‐electron systems using a semiempirical CNDO‐type Hamiltonian. The algorithm used is based on the Clifford algebra realization of the Rumer–Weyl basis presented by Paldus et al. Using this version of the CNDO–VB approach, the effect of the metal hybridization in the electronic delocalization of metallacyclobutadienes is discussed. © 1994 John Wiley & Sons, Inc.