Chemicals

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General Information

Chrome Alum

Chrome alum is one of the possible combinations of alum. There is also potassium alum and ammonium alum. Chrome alum was formerly used in the leather tanning industry. It normally forms a dodecahydrate, but it can also form monohydrates (H2O), dihydrates (2H2O) and hexahydrates (6H2O).[1]

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Chemical & Physical Information

Trivial nameChrome alum
Chemical nameChromium(III) potassium sulfate, dodecahydrate
Other namesChroom aluin (NL,BE)
Type of chemicalIonic compound (salt)
Chemical formulaKCr(SO4)2, 12H2O
CAS number10141-00-1 (anhydrous)
7788-99-0 (dodecahydrate)
Density1.83 g·cm-3
Molar mass499.246 g·mol-1
Melting point89 °C
Boiling point?
SolubleIn water
Solubility (water, 20 °C)240 g·L-1 (dodecahydrate)
Crystal systemCubic
AppearancePurple crystalline solid
ColourPurple
Safety summarySafe
Safety dataMSDS
StorageDry
Extra-

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

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Photos

Chrome Alum

(3 cm)

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Sources

[1] Wikipedia

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