Aluminium oxide hydroxide
Encyclopedia
Aluminium hydroxide oxide or aluminium oxyhydroxide, AlO(OH) is found as one of two well defined crystalline phases, which are also known as the mineral
s boehmite
and diaspore
. The minerals are important constituents of the aluminium
ore
, bauxite
.
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
s boehmite
Boehmite
Boehmite or Böhmite is an aluminium oxide hydroxide mineral, a component of the aluminium ore bauxite. It is dimorphous with diaspore. It crystallizes in the orthorhombic dipyramidal system and is typically massive in habit. It is white with tints of yellow, green, brown or red due to impurities...
and diaspore
Diaspore
Diaspore is a native aluminium oxide hydroxide, α-AlO, crystallizing in the orthorhombic system and isomorphous with goethite. It occurs sometimes as flattened crystals, but usually as lamellar or scaly masses, the flattened surface being a direction of perfect cleavage on which the lustre is...
. The minerals are important constituents of the aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
, bauxite
Bauxite
Bauxite is an aluminium ore and is the main source of aluminium. This form of rock consists mostly of the minerals gibbsite Al3, boehmite γ-AlO, and diaspore α-AlO, in a mixture with the two iron oxides goethite and hematite, the clay mineral kaolinite, and small amounts of anatase TiO2...
.
List of related compounds and minerals
The aluminium oxides, oxide hydroxides, and hydroxides can be summarized as follows:- aluminium oxideAluminium oxideAluminium oxide is an amphoteric oxide with the chemical formula 23. It is commonly referred to as alumina, or corundum in its crystalline form, as well as many other names, reflecting its widespread occurrence in nature and industry...
s- corundumCorundumCorundum is a crystalline form of aluminium oxide with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally clear transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red...
(Al2O3)
- corundum
- aluminium oxide hydroxides
- diasporeDiasporeDiaspore is a native aluminium oxide hydroxide, α-AlO, crystallizing in the orthorhombic system and isomorphous with goethite. It occurs sometimes as flattened crystals, but usually as lamellar or scaly masses, the flattened surface being a direction of perfect cleavage on which the lustre is...
(α-AlO(OH)) - boehmiteBoehmiteBoehmite or Böhmite is an aluminium oxide hydroxide mineral, a component of the aluminium ore bauxite. It is dimorphous with diaspore. It crystallizes in the orthorhombic dipyramidal system and is typically massive in habit. It is white with tints of yellow, green, brown or red due to impurities...
or böhmite (γ-AlO(OH)) - akdalaiteAkdalaiteAkdalaite is a very rare mineral found in Kazakhstan and has the formula 5Al2O3·H2O. It was formerly believed to be 4Al2O3·H2O. It is therefore the same as tohdite an artificailly produced phase. Studies on the crystal structure and spectra indicate that this is an aluminium oxide hydroxide.-...
(5Al2O3·H2O) (once believed to be 4Al2O3·H2O), also called tohdite
- diaspore
- aluminium hydroxideAluminium hydroxideAluminium hydroxide, Al3, ATH, sometimes erroneously called Hydrate of alumina, is found in nature as the mineral gibbsite and its three, much more rare forms, polymorphs: bayerite, doyleite and nordstrandite. Closely related are aluminium oxide hydroxide, AlO, and aluminium oxide, Al2O3,...
s- gibbsiteGibbsiteGibbsite, Al3, is one of the mineral forms of aluminium hydroxide. It is often designated as γ-Al3 . It is also sometimes called hydrargillite ....
(often designated as γ-Al(OH)3, but sometimes as α-Al(OH)3 , sometimes called hydrargillite or hydrargyllite) - bayerite (designated often as α-Al(OH)3 but sometimes as β-Al(OH)3)
- doyleite
- nordstrandite
- gibbsite