KNaFe2Fe3Al2Si4O12

KNaFe2Fe3Al2Si4O12 is described as a complex alkali ferrialuminosilicate with a tectosilicate-type framework. The structure is built from silicate tetrahedra in which silicon and aluminum occupy tetrahedral sites, forming a three-dimensional network. The interstitial sites accommodate potassium and sodium as large-cation occupants, while iron exists in two oxidation states: two Fe2+ ions and three Fe3+ ions, reflecting a mixed-valence character that can influence properties such as color and magnetism.

In composition, the formula indicates a substantial amount of iron present in both ferrous and ferric states alongside aluminum and silicon in tetrahedral coordination. The presence of Fe2+ and Fe3+ suggests redox flexibility within the framework, a feature relevant to studies of iron-bearing aluminosilicates and their electronic or magnetic behavior.

Classification of this exact stoichiometry is not associated with a widely recognized natural mineral species. It may represent an end-member or a synthetic analogue within a broader alkali-aluminosilicate family related to feldspars or feldspathoids, depending on the precise framework topology. As such, KNaFe2Fe3Al2Si4O12 is often treated as a conceptual or laboratory-producible composition rather than a commonly reported natural mineral.

Occurrence and synthesis notes: if encountered in nature, such a composition would be expected in alkali-rich, iron-oxidation-variable environments, though exact stoichiometries of this type are more typically explored in synthetic solid-state experiments to investigate framework substitutions in tectosilicates.