SiO4AlO4Netzwerk

SiO4AlO4Netzwerk refers to a three-dimensional aluminosilicate framework built from corner-sharing SiO4 and AlO4 tetrahedra. In such networks, silicon and aluminum occupy tetrahedral sites connected through shared oxygen atoms, forming a continuous Si–O–Al–O framework that can extend throughout the material.

When aluminum substitutes for silicon in the tetrahedral framework, a negative charge is introduced on the network that must be balanced by extra-framework cations or protons. This framework charge is directly related to the aluminum content and influences properties such as acidity and ion-exchange capacity. The arrangement of Al within the network is constrained by rules of structure, including Loewenstein’s rule, which disfavors adjacent Al–O–Al linkages and affects the distribution of Al in the framework.

The Si/Al ratio is a key parameter that determines material properties. Low Si/Al ratios yield more negative framework charge, increasing acidity and ion-exchange capacity but often reducing hydrothermal stability; higher Si/Al ratios produce more hydrophobic, thermally stable networks with fewer acid sites. These aluminosilicate networks encompass natural minerals, such as feldspars, as well as synthetic materials like zeolites and related microporous silicates.

Applications of SiO4AlO4 networks include catalysis, adsorption, and ion exchange. Zeolites, with their well-defined pore systems, serve as catalysts and molecular sieves in petrochemical processing and environmental remediation. In general, aluminosilicate frameworks are valued for their thermal and chemical durability, tunable acidity, and ability to host cations or protons that participate in catalytic or separative processes. Synthesis and synthesis-directing strategies enable control over Al distribution, pore structure, and framework stability in these networks.