Na2Ca2Si8O2026H2O

Na2Ca2Si8O20·26H2O, sometimes written in condensed form as Na2Ca2Si8O2026H2O, is described in some chemical data sources as a hydrated calcium-sodium silicate. It appears as a framework-type silicate containing sodium and calcium cations balanced by a network of silicon-oxygen tetrahedra and a substantial hydration of water molecules. The exact crystal structure is not widely documented in standard mineral references, and the formula may refer to a specific synthetic phase or to a general hydrate composition within a family of silicates.

Composition and structure

The composition indicates two sodium and two calcium cations per formula unit, with eight silicon and twenty oxygen atoms forming a silicate framework. The notation also indicates twenty-six water molecules occupying structural voids or channels. In such hydrated silicates, the framework is typically built from SiO4 tetrahedra that share oxygen atoms, while the Na+ and Ca2+ ions balance the framework charge and water molecules reside in transient or fixed positions within the porous structure. The precise arrangement can vary with synthesis conditions and hydration state.

Occurrence and synthesis

Information on natural occurrence of this exact formula is limited, and it may be encountered primarily as a synthetic phase produced through hydrothermal or solvothermal methods, or as a specific hydrated silicate in databases. If synthesized, room-temperature handling and controlled dehydration are important factors that affect stability and structure.

Properties and potential applications

As a hydrated silicate, the material is expected to be crystalline or microcrystalline with substantial water content. Dehydration upon heating alters the framework and can change porosity and ion-exchange properties. Such materials are of interest in contexts like ion exchange, adsorption, or as catalyst supports, though specific performance depends on the precise structure and hydration level.

See also

Hydrated silicates, zeolites, ion-exchange materials, silicate frameworks.