Aluminum ammonium sulfate
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Description
A white crystalline powder that is also called ammonium alum. Aluminum ammonium sulfate occurs naturally as the mineral tschermigite. It is used in baking powders, dyeing textiles, tanning leathers, and as a substrate for lake pigments. Ammonia alum is also used in developing baths for black and white photographs.
Synonyms and Related Terms
ammonia alum; ammonium aluminum sulfate; alum NF; aluminum ammonium sulphate (Br.); tschermigite
Other Properties
Soluble in water, glycerol. Insoluble in ethanol. Crystals are fibrous and deliquescent
| Composition | AlNH4(SO4)2-12H2O |
|---|---|
| Mohs Hardness | 1.5-2.0 |
| Melting Point | 94.5 |
| Density | 1.645 |
Hazards and Safety
Skin contact may cause allergies.
Additional Information
Web Minerals: Tschermigite
Sources Checked for Data in Record
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 33
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
- John and Margaret Cannon, Dye Plants and Dyeing, Herbert Press, London, 1994
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 335