Title: Aluminum Ammonium Sulfate
CAS Registry Number: 7784-25-0
Synonyms: Burnt ammonium alum; exsiccated ammonium alum
Molecular Formula: AlH4NO8S2
Molecular Weight: 237.15
Percent Composition: Al 11.38%, H 1.70%, N 5.91%, O 53.97%, S 27.04%
Line Formula: AlNH4(SO4)2
Literature References: Prepn:
Gmelins, Aluminum (8th ed)
35B, pp 508-515 (1934). Crystal structure of dodecahydrate: Larson, Cromer,
Acta Crystallogr. 22, 793 (1967).
Properties: About 97-98% pure, the balance is chiefly excess Al2O3. White powder. One gram dissolves in about 20 ml cold, 1.5 ml boiling water, usually incompletely; practically insol in alcohol.
Keep well closed.
Derivative Type: Dodecahydrate
Synonyms: Ammonium alum
Properties: It is about 99.5% pure. Colorless crystals, white granules or powder; styptic taste. d 1.65. mp 94.5°. At about 250° becomes anhydr; decomposes above 280°. One gram dissolves in 7 ml water, 0.5 ml boil. water; freely soluble in glycerol; practically insol in alc. The aq soln is acid to litmus; pH of 0.05 molar soln 4.6.
Melting point: mp 94.5°
Density: d 1.65
Use: Purifying drinking water; in baking powders; dyeing and printing fabrics; manuf pigments, lakes, artificial gems, paper, vegetable glue, marble and porcelain cements; fireproofing; tanning; electrolytic copperplating.
See also Aluminum Potassium Sulfate.
Therap-Cat: Astringent, styptic.
Therap-Cat-Vet: Astringent, styptic.
Keywords: Astringent.
