“…As an important bridge between macroscopic matter and microscopic particles, nanoclusters generally have definite atomic compositions, tunable nanoscale sizes, abundant geometric structures, and unique electronic characteristics, which can endow them with great potential for application in catalysis, energy storage, and biomedicine. − Significantly, one of the most representative subfamilies of nanoclusters are polyoxometalates (POMs), which are generally nanosized aggregates generated by early transition-metal ions through oxygen atoms and display variable architectures, special electronic configurations, as well as reversible electron transfer capability. − Because of the inseparable correlation between geometrical structures and intrinsic nature, it has been widely acknowledged that some properties of nanoclusters can be deliberately regulated by structure manipulation. , Thus, exploring and discovering new-type POMs with appealing structures and innovative properties have been an appealing topic in cluster science. To achieve this end, one significant strategy to enrich a library of POM databases is to design and search for novel lacunary POM building units (PBUs), whose vacancies can be readily attacked and functionalized with additional functional components, especially metal ions, and thus construct innovative POMs.…”