AlO4

AlO4 is a chemical formulation that most often appears as a tetrahedral oxide unit centered on aluminum. In ordinary chemistry, a stable neutral molecule with the formula AlO4 is not known; aluminum typically exhibits a +3 oxidation state and forms oxides and oxyanions rather than a discrete neutral AlO4 species.

In solid-state and materials chemistry, AlO4 units are a common structural motif. Tetrahedral aluminum centers bonded to four oxide ligands occur in aluminates and aluminosilicates. In aluminosilicate frameworks, for example, AlO4 tetrahedra can substitute for SiO4 tetrahedra, generating a negatively charged framework that is balanced by extra-framework cations such as Na+ or K+. This AlO4-based motif is central to the structure of many zeolites and related materials, where the arrangement of AlO4 units influences acidity, ion-exchange properties, and catalytic behavior.

In aqueous environments, aluminum chemistry is dominated by hydrolysis and hydrated species rather than discrete AlO4 units. Common aqueous species include Al3+ at low pH and various hydroxo complexes, such as [Al(OH)4]− in strongly basic solutions. The AlO4 description is therefore most appropriate for solid frameworks rather than solution chemistry.

See also: aluminates, aluminosilicates, zeolites, aluminum oxide, aluminum hydroxide.