Cornersharing

Corner sharing is a mode of structural linkage in crystalline solids where adjacent coordination polyhedra are joined at a single vertex, or corner, typically via a shared oxide atom. This contrasts with edge sharing, where polyhedra share an entire edge, and face sharing, where they share a full face. Corner sharing is especially common in oxide and silicate minerals, where silicon-oxygen tetrahedra (SiO4) connect through corners to build extended networks.

In silicates, corner-sharing tetrahedra form three-dimensional frameworks as seen in quartz and many feldspars. Zeolites rely on corner-sharing tetrahedra to create porous, open structures that host channels and cavities. Octahedrally coordinated cations (MO6) can also participate in corner-sharing networks, as in certain perovskite-type oxides, where the octahedra connect through corners to create a robust three-dimensional framework.

The mode of sharing influences material properties. Corner-sharing networks tend to produce highly connected yet relatively open frameworks, affecting density, thermal behavior, and vibrational characteristics. They also influence how silicate and oxide minerals polymerize and classify, with the degree of corner sharing contributing to overall crystallographic connectivity.

In crystallography and mineralogy, identifying whether polyhedra share corners, edges, or faces helps describe the topology and stability of a structure. Corner sharing remains a fundamental concept for understanding the architecture of many silicate and oxide materials.