AlOOH

Aluminum oxyhydroxide, with the chemical formula AlOOH, is a compound that occurs as natural mineral phases and is widely synthesized for industrial use. The name boehmite typically refers to the gamma polymorph of AlOOH (γ-AlOOH), while diaspore denotes the alpha polymorph (α-AlOOH). Both are polymorphs of aluminum oxyhydroxide and together with other forms represent a common aluminum precursor.

The structure consists of octahedrally coordinated aluminum centers (AlO6) linked into layered sheets by shared edges and bridged by hydroxide groups. This layered arrangement gives AlOOH a relatively high specific surface area, which is advantageous for catalysis and adsorption. Upon heating, AlOOH dehydrates to form alumina (Al2O3); the exact alumina phase produced depends on temperature and heating conditions.

Occurrence and production: natural boehmite can be found in certain bauxite ores and hydrothermally altered aluminous rocks. Industrially, AlOOH is prepared synthetically by precipitation from aluminum salts, hydrothermal synthesis, or other solid-state transformations. It is a common intermediate or precursor to aluminum oxide during processing.

Applications: AlOOH and its nanoscale forms are important as high-surface-area materials. They are used as catalyst supports and adsorbents, and as precursors to various forms of alumina used in ceramics, refractories, and catalysts. Because of its dehydration behavior, boehmite is also employed in flame-retardant formulations and as a filler or stabilizer in polymer composites, where controlled release of water upon heating can contribute to performance.