Tris(alkene) complexes of the form [M(h 2 -R2C=CR2)3] n+ (M = Ni, Pd, Pt, n = 0; Cu, Ag, Au, n =1) are a useful exemple of this continuum. The bonding between the transition metal atom and an array of alkene ligands in these complexes can be conceptualised in terms of the Dewar-Chatt-Duncanson model. Each metal-alkene interaction is constructed from s-donation and pbackdonation components. If the s-donation component of bonding dominates the bonding interaction, a trigonal planar geometry can be assigned. However, as pbackdonation -and the metallocyclopropane contribution -becomes more important (causing a slight increase in θ), the bonding can be thought of as moving along the continuum from trigonal planar toward hexagonal planar. It is not possible for these complexes to obtain a true hexagonal planar geometry (θ = 60°), in part because the carbon atoms in each alkene ligand are still connected by a s-bond, which precludes achieving a high value of θ.