Chemicals

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General Information

Potassium Alum

Potassium alum is one of the possible combinations of alum. There is also chrome alum and ammonium alum.[1]

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Chemical & Physical Information

Trivial namePotassium alum
Chemical namePotassium aluminum sulfate, dodecahydrate
Other namesKalium aluin (NL,BE)
Type of chemicalIonic compound (salt)
Chemical formulaKAl(SO4)2, 12H2O
CAS number10043-67-1 (anhydrous)
7784-24-9 (dodecahydrate)
Density1.76 g·cm-3
Molar mass258.207 g·mol-1
Melting point92-93 °C
Boiling point200 °C
SolubleIn water
Solubility (water, 20 °C)118 g·L-1 Potassium alum solubility graph. (anhydrous)
Crystal systemCubic
AppearanceWhite crystalline solid
ColourWhite
Safety summarySafe
Safety dataMSDS
StorageDry
Extra-

For more information, also look at the potassium alum crystals.

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Photos

Potassium Alum

(3 cm)

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Sources

[1] Wikipedia

[2] Specimen from my personal collection, photo taken by me.

[3] Mullin J.W. - Crystallization, 2001