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Aluminium hydroxide, Al 3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric, i.e., it has both basic and acidic properties.
One third of the potential octahedral spaces are missing a central aluminium. The result is a neutral sheet: with aluminium as a +3 ion and hydroxide a −1 ion, the net cationic charge of one aluminium per six hydroxides is (+3)/6 = +1/2, and likewise the net anionic charge of one hydroxide per two aluminium atoms is (−1)/2 = −1/2.
Aluminium hydroxide oxide or aluminium oxyhydroxide, AlO(OH) is found as one of two well defined crystalline phases, which are also known as the minerals boehmite and diaspore. The minerals are important constituents of the aluminium ore , bauxite .
Many metals (such as zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Aluminium oxide (Al 2 O 3) is an example of an amphoteric oxide. Amphoterism depends on the oxidation states of the oxide. Amphoteric oxides include lead(II) oxide and zinc oxide, among many others. [2]
Aluminium (or aluminum in North American English) is a chemical element; it has symbol Al and atomic number 13. Aluminium has a density lower than that of other common metals, about one-third that of steel. It has a great affinity towards oxygen, forming a protective layer of oxide on the surface when exposed to air.
The process ends with precipitation of aluminium hydroxide, Al(OH) 3. This is useful for clarification of water, as the precipitate nucleates on suspended particles in the water, hence removing them. Increasing the pH even further leads to the hydroxide dissolving again as aluminate, [Al(H 2 O) 2 (OH) 4] −, is formed.
Bauxite, a basic hydroxide of aluminium, is the principal ore from which the metal is manufactured. [12] Similarly, goethite (α-FeO(OH)) and lepidocrocite (γ-FeO(OH)), basic hydroxides of iron , are among the principal ores used for the manufacture of metallic iron.
Hydroxyaluminium(I), also known as Aluminium(I) hydroxide, is an inorganic chemical with molecular formula AlOH. It consists of aluminium in the +1 oxidation state paired with a single hydroxide . It has been detected as a molecular substance in the envelope of an oxygen -rich red supergiant star , a place where substances containing metals or ...