Aluminium hydroxide
| Aluminium hydroxide | | |
| General |
|---|
| Systematic name | Aluminium(III) hydroxide |
| Other names | Aluminium hydroxide,
Hydrated alumina |
| Molecular formula | Al(OH)3 |
| Molar mass | 78.00344 g/mol |
| Appearance | White amorphous powder. |
| CAS number | [] |
| Properties |
|---|
| Density and phase | 2.4 g/cm3, solid. |
| Solubility in water | Insoluble. |
>| Melting point?°C |
| Boiling point | ?°C |
| Acidity (pKa) | N/A |
| Hazards |
|---|
| MSDS | External MSDS |
| EU classification | Irritant (I) |
| NFPA 704 | N/A |
| R-phrases | , , |
| S-phrases | , |
| Flash point | Non-flammable. |
| RTECS number | N/A |
| Supplementary data page |
|---|
| Structure & properties | n, εr, etc. |
| Thermodynamic data | Phase behaviour
Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds |
|---|
| Other s | None. |
| Related compounds | Sodium oxide,
aluminium oxide hydroxide. |
Except where noted otherwise, data are given for
materials in their standard state (at 25°C, 100 kPa)
Infobox disclaimer and references |
|
Aluminium hydroxide, Al(OH)
3, is the most stable form of aluminium in normal conditions. As found in nature it is known as the mineral
gibbsite. Closely related are
aluminium oxide hydroxide, AlO(OH), and
aluminium oxide, Al
2O
3, differing only by loss of water. These compounds together are the major components of the aluminium
ore,
bauxite.
The character of 'aluminium hydroxide' has been controversial. It is safe to say that a simple scheme of Al
3+ ions and OH
- ions is oversimplified. More and less hydrated forms are very common. Some people write Al
2O
3.
xH
2O instead.
Aluminium hydroxide is
amphoteric. In strongly acid conditions, Al(OH)
2+ is formed; in strongly basic conditions, Al(OH)
4- is formed. These are the main ions in dilute solutions; in concentrated solutions, polymeric ions are formed which can be quite complex.
Salts of the anion Al(OH)
4- (or similar, such as AlO
2-) are sometimes called
aluminates.
Al(OH)
3 has a molar mass of 78.01.
When used, aluminum hydroxide neutralizes the excess acid. For example,Al(OH)
3 + 3HCl yields AlCl
3 + 3H
2O.
Pharmacologically this compound, also known as
Alu-Cap or
Aludrox, is used as an
antacid. It binds with the excess acid in the stomach, thus reducing its acidity. This decrease of acidity of the contents of the stomach may in turn help to relieve the symptoms of
ulcers,
heartburn or
dyspepsia. It can also cause constipation and is therefore often used with
magnesium carbonate.This compound is also used to control phosphate levels in the blood for people suffering from kidney failure. However, there are unverified claims that excessive consumption of aluminium is a cause of
Alzheimer's disease.
Galbraith, A; Bullock, S; Manias, E. Hunt, B. & Richards, A. (1999). Fundamentals of pharmacology: a text for nurses and health professionals. Harlow: Pearson Education Ltd. p482.
*
International Chemical Safety Card 0373*
External MSDS Sheet.
