Group quintuple bonds

The metal-metal bond order in transition metal M2-type molecules and in transition metal complexes may be higher than in the case of the main group elements because of the participation of the d orbitals. The diatomic molecule M02 has a quintuple bond, with an electronic configuration of (the Mo-Mo... 

Five helical strands associate laterally leading to a quintuple helical braid (Figure 29). The authors [49] suggested that the formation of this supramolecular assembly may be due to edge-to-face interactions between the pyridine units and the phenyl groups in conjunction with van der Waals interactions. Finally, the quintuple helices associate laterally to form the crystal. In this supramolecular synthesis H-bonding plays a role only in the first level of the assembly process via a single-stranded H-bonded helical network. 

---