Acidopentaaminecobalt(III) Complexessquare-planar arrangement is more suitable than an octahedral arrangement for bonding,, then the contrasting behavior of octahedral systems and square-planar systems can be understood. Evidence in the form of MO calculations,11 spectroscopic studies,11'12 and the results presented here support point (1) above; the second and third points are well established.22 There does not seem to be a need for two theories (symbiosis and MO) to account for the contrasting behavior discussed above. It seems unlikely that any theory (22) L. D.