KNa2Al4Si8O22OH2

KNa2Al4Si8O22(OH)2 is the chemical composition of a framework aluminosilicate that can be described as a potassium sodium aluminum silicate hydroxide. The formula conveys a three-dimensional network of silicon and aluminum tetrahedra linked through shared oxygen, with potassium and sodium cations balancing the framework’s negative charge and hydroxide groups completing the structure. The aluminum-to-silicon ratio is 4 to 8, i.e., 1:2, a characteristic that influences the framework’s connectivity and properties.

Structurally, the material is described as a tectosilicate-type framework in which SiO4 and AlO4 tetrahedra share corners to form a rigid three-dimensional lattice. The presence of OH groups indicates a hydrous phase, and the alkali cations occupy channels or cavities within the framework. Depending on the precise topology and synthesis conditions, related materials can resemble zeolites or feldspathoid-like aluminosilicates, with variability in porosity and cation-content.

Occurrence and applications are largely governed by synthesis rather than natural occurrence. There is limited documentation of this exact composition as a naturally recognized mineral; it is more commonly encountered as a synthetic phase in research on aluminosilicate frameworks. Such materials are of interest for ion exchange, adsorption, and catalytic applications because their open networks can host exchangeable cations and enable molecular access to active sites.

See also: Zeolites, Aluminosilicates, Feldspars, Silicate minerals, Hydrothermal synthesis.