From the above, it is clear that the coordination chemistry of vanadium (thus far) is dominated by the V V ion. There are no examples of homovalent V IV or V III species in the literature, and there is just one mixed valent species. The vast majority of complexes have been synthesised via air-and moisture-free techniques in nonprotic solvents. Very few, if any, have been made in the presence of air/moisture using standard benchtop techniques in protic solvents, and none have been made via high temperature/pressure (solvothermal) methods. Most are of small nuclearity, with dimers being particularly prevalent. Larger species tend to be heterometallic, and the majority of these contain s-block metal ions. This perhaps suggests that the increased flexibility in the coordination number and geometry of the s-block metal ions allows them to be more easily accommodated into the framework of the cluster, whose (often asymmetric) topology is dictated by the conformation of the calix [8]arene. There are no examples of heterometallic V-3d, V-4f or V-5f clusters. Clearly there remains a vast amount of chemistry to be explored before the coordination chemistry of vanadium is fully mapped out. There does not appear to be a common/dominant structural theme arising from the metallic skeletons of the V clusters thus far, albeit {V2} dimers, {V4} butterflies and {V4} tetrahedra are the most common. The calix [8]arene ligands in these clusters show a variety of conformations and are either fully deprotonated, TBC [8], or singly/doubly deprotonated H1TBC [8]/H2TBC [8], as one might expect given the coordination chemistry is primarily established for the V V ion. The most common coordination motif of the ligand is as an η 2 -chelate with two neighbouring O(Ph) atoms bonded to the same V centre.