In the theory of atoms in molecules (AIM), the charge density is usually a suitable tool for bonding analyses. However, problems arise in some cases. So, no direct Co-Co bond is found in Co-2(CO)(8). It is shown that the energy density gives deeper insight into the bonding properties. This is demonstrated for Co-2(CO)(8), Co-4(CO)(12), and Co-2(CO)(6)(InMe)(2). The strategy is not restricted to transition metal compounds; it should be useful to identify any weak bonding or antibonding interactions.