Requests: If you need specific information on this remedy - e.g. a proving or a case info on toxicology or whatsoever, please post a message in the Request area www.homeovision.org/forum/ so that all users may contribute.
The earliest citation given in the Oxford English Dictionary for any word used as a name for this element is alumium, which British chemist and inventor Humphry Davy employed in 1808 for the metal he was trying to isolate electrolytically from the mineral alumina.
Davy settled on aluminum by the time he published his 1812 book Chemical Philosophy: "This substance appears to contain a peculiar metal, but as yet Aluminum has not been obtained in a perfectly free state, though alloys of it with other metalline substances have been procured sufficiently distinct to indicate the probable nature of alumina." But the same year, an anonymous contributor to the Quarterly Review, a British political-literary journal, in a review of Davy's book, objected to aluminum and proposed the name aluminium, "for so we shall take the liberty of writing the word, in preference to aluminum, which has a less classical sound."
Minerals; Inorganic; Column Three
Description of the substance
Aluminium chloride (AlCl3) is a compound of aluminium and chlorine. The anhydrous material has a very interesting structure: despite being the halide of a highly electropositive metal, its bonding is principally covalent. This is seen in the fact that it has a low melting and boiling point (it sublimes at 178 °C), and it conducts electricity poorly in the liquid state , unlike ionic halides such as sodium chloride. It exists in the solid state as a six-coordinate layer lattice. This melts to a four-coordinate dimer, Al2Cl6, which can vaporise, but at higher temperatures this dissociates into a simple AlCl3 species analogous to BF3.
Aluminum chloride is highly deliquescent, and it can explode in contact with water because of the high hydration. It partially hydrolyses with H2O, forming some hydrogen chloride and/or hydrochloric acid. Aqueous solutions of AlCl3 are fully ionized, and thus conduct electricity well. Such solutions are found to be acidic, indicating that partial hydrolysis of the Al3+ ion is occurring.
AlCl3 is probably the most commonly used Lewis acid and also one of the most powerful. It finds widespread application in the chemical industry as a catalyst for Friedel-Crafts reactions, both acylations and alkylations. It also finds use in polymerization and isomerization reactions of hydrocarbons.
The structure of aluminium chloride is often represented as Al2Cl6 under all conditions. It isn’t.
At room temperature the solid (r = 2.44 g cm-3) has an ionic layer lattice (fig1), the aluminium being 6-coordinate. It consists of hexagonal close-packed layers of chloride ions in which two-thirds of the octahedral holes between every other pair of Cl planes are occupied by aluminium ions. The pictures at right show the lattice, and two layers of the lattice separated to show the positions of the aluminium ions.
There are dramatic changes at the melting temperature of 192.4oC (at 1700mmHg). Aluminium becomes 4-coordinate as the covalent molecular dimer Al2Cl6 is formed. The volume of the solid increases dramatically by about 85% (r = 1.31 g cm-3) and the electrical conductivity, which increases from zero at the ordinary temperature to become quite high just below the melting temperature, becomes virtually zero. There is thus a considerable change of bonding and structure at this temperature (fig2).
The dimer is also the main species in the gas phase below 200oC, this dissociating increasingly (DHdissoc = + 63 kJ mol-1) into trigonal planar AlCl3 molecules as the temperature is raised 2, 3.
Aluminium bromide and iodide do not share these properties, existing as dimers in the solid phase and not showing such dramatic changes on melting.