Tetraperchloratoaluminates are salts of the tetraperchloratoaluminate anion,
l(ClO4)4sup>−. The anion contains
aluminium
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
tetrahedrally surrounded by four
perchlorate
A perchlorate is a chemical compound containing the perchlorate ion, , the conjugate base of perchloric acid (ionic perchlorate). As counterions, there can be metal cations, quaternary ammonium cations or other ions, for example, nitronium cat ...
groups. The perchlorate is covalently bonded to the aluminium, but perchlorate is much more well known as an ion. The covalent bond to aluminium distorts the perchlorate and renders it unstable.
Related chemicals are the haloperchloroatoaluminates, where there is one perchloro group attached to aluminium, and three halogens such as chlorine (chloroperchloroatoaluminates) or bromine (bromoperchloroatoaluminates).
Formation
Nitronium tetraperchloratoaluminate is made from exact amounts of
nitronium perchlorate
Nitronium perchlorate, NO2ClO4, also known as nitryl perchlorate and nitroxyl perchlorate, is an inorganic chemical, the Salt (chemistry), salt of the perchlorate anion and the nitronium ion, nitronium cation. It forms colorless monoclinic crysta ...
and anhydrous
aluminium chloride
Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms a hexahydrate with the formula , containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are col ...
combined in liquid
sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is r ...
.
Ammonium tetraperchloratoaluminate can be formed by three moles of
nitronium perchlorate
Nitronium perchlorate, NO2ClO4, also known as nitryl perchlorate and nitroxyl perchlorate, is an inorganic chemical, the Salt (chemistry), salt of the perchlorate anion and the nitronium ion, nitronium cation. It forms colorless monoclinic crysta ...
, one mole of anhydrous
aluminium chloride
Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms a hexahydrate with the formula , containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are col ...
, and one mole of
ammonium perchlorate
Ammonium perchlorate ("AP") is an inorganic compound with the formula . It is a colorless or white solid that is soluble in water. It is a powerful oxidizer. Combined with a fuel, it can be used as a rocket propellant called ammonium perchlorat ...
combined in liquid sulfur dioxide.
Properties
The tetraperchloratoaluminates are yellowish crystalline solids. They are stable up to 50 °C.
Above this temperature they decompose to
hexaperchloratoaluminates which are more temperature stable.
References
{{Perchlorates
Aluminium complexes
Perchlorates
Anions