The introduction of coinage metals (CMs) into lacunary polyoxometalates (POMs) to construct CM-substituted POMs (CM-POMs) has attracted increasing interest over the past decade. This is because CM-POMs combine the unique structural features of POMs and CMs and have promising applications in photocatalysis, luminescence, magnetic materials, etc. In this review, the structural characteristics, synthesis methods, and applications of CM-POMs are summarized in three categories according to the type of their metal core element: Cu-, Ag-, and Au-substituted POMs. Furthermore, this paper discusses the current challenges regarding investigations into the design and properties of CM-POMs.

Polyoxotantalates (POTas) are an important branch of polyoxometalates (POMs) that remain largely undeveloped compared with other members of the POM family including polyoxovanadates, polyoxotungstates, polyoxomolybdates, and polyoxoniobates. Owing to their promising applications in diverse fields such as photo/electrocatalysis, ion conduction, environmental protection, and magnetism, the development of synthetic strategies for new POTas has attracted continuous interest over the past decades. This review summarizes the current status in the development of POTas, including their synthetic methods, crystal structures, physicochemical properties, and potential applications. Additionally, synthetic challenges and prospects are also discussed. It is hoped that this review will be of reference value for the further development of POTas.