Aluminium sulfate
General
Systematic name	Aluminium sulfate hexadecahydrate
Other names	Cake alum Filter alum Papermaker's alum alumogenite Aluminum sulfate Aluminium sulphate
Molecular formula	Al2(SO4)3.16H2O
Molar mass	630.40 g/mol
Appearance	white crystalline solid
CAS number	[16828-11-8]
EINECS number	233-135-0
Properties
Density and phase	2.71 g/cm3, solid
Solubility in water	31.3 g/100 ml (0 °C)
In ethanol	Slightly soluble (anh.) Insoluble (hydrate)
Melting point	770°C decomp.
Structure
Coordination geometry	?
Crystal structure	monoclinic (hydrate)
Safety data
PEL-TWA (OSHA)	—
RTECS number	BD1700000
Supplementary data page
Structure & properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other cations	Gallium sulfate Magnesium sulfate
Related compounds	See Alum
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references

Aluminium sulfate is a widely used industrial chemical. It is sometimes incorrectly referred to as alum, as it is closely related to this group of compounds. It occurs naturally as the mineral alunogenite. It is frequently used in the purification of drinking water supplies, and also in paper manufacturing. Image File history File links File links The following pages link to this file: Aluminium sulfate ... IUPAC nomenclature is a systematic way of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of an element or chemical compound. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... The EINECS number (for European Inventory of Existing Chemical Substances) is a registry number given to each chemical substance commercially available in the European Union between 1 January 1971 and 18 September 1981. ... Density (symbol: ρ - Greek: rho) is a measure of mass per unit of volume. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... A substance is soluble in a fluid if it dissolves in the fluid. ... Water has the chemical formula H2O, meaning that one molecule of water is composed of two hydrogen atoms and one oxygen atom. ... Ethanol, also known as ethyl alcohol or grain alcohol, is a flammable, colorless chemical compound, one of the alcohols that is most often found in alcoholic beverages. ... Liquids and solids (powders) are anhydrous if they are without water, i. ... The melting point of a solid is the temperature at which it changes state from solid to liquid. ... The coordination geometry of an atom is the geometrical pattern formed by its neighbors in a molecule or a crystal. ... Rose des Sables (Sand Rose), formed of gypsum crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. ... The Permissible Exposure Limit (PEL or OSHA PEL) is a legal limit in the United States for personal exposure to a substance, usually expressed in parts per million (ppm). ... The United States Occupational Safety and Health Administration (OSHA) was created by Congress under the Occupational Safety and Health Act, signed by President Richard M. Nixon on December 29, 1970. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The refractive index of a material is the factor by which the phase velocity of electromagnetic radiation is slowed relative to vacuum. ... The dielectric constant εr (represented as or K in some cases) is defined as the ratio: where εs is the static permittivity of the material in question, and ε0 is the vacuum permittivity. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... IR spectrum of a thin film of liquid ethanol. ... Nuclear Magnetic Resonance Spectroscopy is the name given to the technique which exploits the magnetic properties of nuclei. ... Mass spectrometry is a technique for separating ions by their mass-to-charge (m/z) ratios. ... An ion is an atom or group of atoms with a net electric charge. ... Magnesium sulfate (commonly called Epsom salts or bitter salts in hydrated form) is a chemical compound with the formula MgSO4·7H2O. Origin Epsom salt was originally prepared by boiling down mineral waters at Epsom, England and afterwards prepared from sea water. ... For alum meaning graduate, see Alumn. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... For alum meaning graduate, see Alumn. ... This article is about minerals in the geologic sense; for nutrient minerals see dietary mineral; for the band see Mineral (band). ...

Aluminium sulfate is rarely, if ever, encountered as the anhydrous salt. It forms a number of different hydrates, of which the hexadecahydrate is the most common. Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. ...

It can also be very effective at killing Spanish slugs.

Preparation

Aluminium sulfate, Al₂(SO₄)₃.18H₂O, may be made by dissolving aluminium hydroxide, Al(OH)₃, in sulfuric acid, H₂SO₄: Aluminium hydroxide, Al(OH)3, is the most stable form of aluminium in normal conditions. ... Sulfuric acid (British English: sulphuric acid), H2SO4, is a strong mineral acid. ...

2Al(OH)₃ + 3H₂SO₄ + 12H₂O --> Al₂(SO₄)₃.18H₂O

Uses

Aluminium sulfate is used in water purification and as a mordant in dyeing and printing textiles. In water purification, it adsorbs impurities which are removed as the particulate settles to the bottom of the container. A mordant is a substance used to set dyes. ... In chemistry, adsorption of a substance is its concentration on a particular surface. ...

When dissolved in a large amount of neutral or slightly-alkaline water, aluminium sulfate produces a gelatinous precipitate of aluminium hydroxide, Al(OH)₃. In dyeing and printing cloth, the gelatinous precipitate helps the dye adhere to the clothing fibers by rendering the pigment insoluble. Aluminium hydroxide, Al(OH)3, is the most stable form of aluminium in normal conditions. ...

Aluminium sulfate is the active ingredient of some anti-perspirants; however, beginning in 2005 the US Food and Drug Administration no longer recognized it as a wetness reducer. The United States Food and Drug Administration (FDA) is the government agency responsible for regulating food (human and animal), dietary supplements, drugs (human and animal), cosmetics, medical devices (human and animal), biologics and blood products in the United States. ...

See also

• Camelford, a town in Cornwall (UK) where the local water supplies were accidentally contaminated with aluminium sulfate.

Camelford is a town in Cornwall, England. ... Motto: Onan hag oll (Cornish: One and all) Cornwall, England Geography Status Ceremonial and (smaller) Administrative county Traditional county Duchy of Cornwall Region South West England Area - Total - Admin. ...

Suppliers

• Sigma-Aldrich Co.

External links

• International Chemical Safety Card 1191
• NIOSH Pocket Guide to Chemical Hazards

Books

Pauling, Linus (1970) General Chemistry, W.H. Freeman: San Francisco. ISBN 0-486-65622-5