Ammonium aluminium sulfate

From Infogalactic: the planetary knowledge core
(Redirected from Ammonium alum)
Jump to: navigation, search
Ammonium aluminium sulfate
200px
Names
IUPAC name
Aluminium ammonium bis(sulfate)[citation needed]
Other names
Ammonium alum
Tschermigite
Identifiers
7784-25-0 YesY
7784-26-1 (dodecahydrate) YesY
ChemSpider 2297489 YesY
56419 (dodecahydrate) YesY
EC Number 232-055-3
Jmol 3D model Interactive image
RTECS number WS5640010
  • InChI=1S/Al.H3N.2H2O4S/c;;2*1-5(2,3)4/h;1H3;2*(H2,1,2,3,4)/q+3;;;/p-3 YesY
    Key: LCQXXBOSCBRNNT-UHFFFAOYSA-K YesY
  • InChI=1/Al.H3N.2H2O4S/c;;2*1-5(2,3)4/h;1H3;2*(H2,1,2,3,4)/q+3;;;/p-3
    Key: LCQXXBOSCBRNNT-DFZHHIFOAY
  • [Al+3].[O-]S(=O)(=O)[O-].[O-]S([O-])(=O)=O.[NH4+]
Properties[1]
(NH4)Al(SO4)2
Molar mass 237.15 g/mol (anhydrous)
453.33 g/mol (dodecahydrate)
Appearance white crystals
Density 2.45 g/cm3 (anhydrous)
1.64 g/cm3 (dodecahydrate)
Melting point 93.5 °C (200.3 °F; 366.6 K) (dodecahydrate)
Boiling point 120 °C (248 °F; 393 K) dehydr. (dodecahydrate)
15 g/100 ml (20 °C, dodecahydrate)
Structure[1]
Hexagonal (anhydrous)
Cubic (dodecahydrate)
Octahedral (Al3+)
Vapor pressure {{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Ammonium aluminium sulfate, also known as ammonium alum or just alum, is a white crystalline double sulfate usually encountered as the dodecahydrate, formula (NH4)Al(SO4)2·12H2O. It is used in small amounts in a variety of niche applications. The dodecahydrate occurs naturally as the rare mineral tschermigite.[1]

Production and basic properties

Ammonium alum is made from aluminium hydroxide, sulfuric acid and ammonium sulfate. It forms a solid solution with potassium alum. Pyrolysis leaves alumina. Such alumina is used in the production of grinding powders and as precursors to synthetic gems.[2]

Uses

Ammonium alum is not a major industrial chemical or a particularly useful laboratory reagent, but it is inexpensive and nontoxic, which invites many niche applications. It is used in water purification, in vegetable glues, in porcelain cements, in deodorants and in tanning, dyeing and in fireproofing textiles.[3] The pH of the solution resulting from the topical application of ammonium alum with perspiration is typically in the slightly acid range, from 4 to 5.[4]

Ammonium alum is a common ingredient in animal repellant sprays.[5][6][7]

Toxicology

Aluminium sulfate, closely related to ammonium alum, is nontoxic with an LD50 of 6207 mg/kg. No human or ecological (for reduced concentrations) toxicity registered.[8]

References

  1. 1.0 1.1 1.2 Lua error in package.lua at line 80: module 'strict' not found..
  2. Otto Helmboldt, L. Keith Hudson, Chanakya Misra, Karl Wefers, Wolfgang Heck, Hans Stark, Max Danner, Norbert Rösch "Aluminum Compounds, Inorganic" in Ullmann's Encyclopedia of Industrial Chemistry 2007, Wiley-VCH, Weinheim.doi:10.1002/14356007.a01_527.pub2
  3. Lua error in package.lua at line 80: module 'strict' not found..
  4. Lua error in package.lua at line 80: module 'strict' not found..
  5. Lua error in package.lua at line 80: module 'strict' not found..
  6. Lua error in package.lua at line 80: module 'strict' not found..
  7. Lua error in package.lua at line 80: module 'strict' not found..
  8. Lua error in package.lua at line 80: module 'strict' not found..