CaNaAlFe2SiO42OH2nH2O

CaNaAlFe2SiO4(OH)2·nH2O, sometimes written as CaNaAlFe2SiO42OH2nH2O, is a hydrated calcium-sodium aluminum iron silicate. The generalized formula expresses a family of compositions in which water molecules are intercalated in the crystal structure (n can vary), rather than a single fixed compound. The name reflects the major cations and the aluminosilicate framework, with hydration indicated by the water molecules.

Composition and structure: The framework is built from silicon and aluminum tetrahedra linked through shared oxygens, with iron incorporated in the structure in some form. Calcium and sodium provide charge balance in interstitial or framework sites. Hydroxyl groups (OH) are part of the structure, and water molecules occupy interstitial positions. Variation in silicon-to-aluminum-to-iron ratios and the hydration level can influence whether the material adopts layered or framework-like motifs, as well as the overall crystallinity and cation arrangement.

Physical properties: Properties depend on composition and hydration state. In general, such hydrated aluminosilicates are moderately soft to relatively dense, with color and optical characteristics influenced by the iron content and its oxidation state. Dehydration can occur upon heating, which alters the structure and may reduce interlayer spacing or collapse certain motifs. The exact magnetic, thermal, and catalytic properties are contingent on the distribution of Fe and the degree of hydration.

Occurrence and significance: As a hydrated aluminosilicate formulation, CaNaAlFe2SiO4(OH)2·nH2O is relevant in discussions of synthetic silicates and natural analogs among hydrated minerals. It may be studied for ion-exchange behavior, adsorption, or catalysis in research contexts, with practical utility depending on structural stability and crystallinity.