Chrome alum

Potassium chromium sulfate
Sample of chrome alum in sample jar
Names
IUPAC name
Chromium potassium sulfate[citation needed]
Other names
Chromium alum[citation needed]
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.352 Edit this at Wikidata
EC Number
  • 233-401-6
MeSH chrome+alum
RTECS number
  • GB6845000
UNII
  • InChI=1S/Cr.K.2H2O4S/c;;2*1-5(2,3)4/h;;2*(H2,1,2,3,4)/q+3;+1;;/p-4
    Key: OIDPCXKPHYRNKH-UHFFFAOYSA-J
  • InChI=1/Cr.K.2H2O4S/c;;2*1-5(2,3)4/h;;2*(H2,1,2,3,4)/q+2;+1;;/p-4
    Key: HIZQQXDAMAATMK-XBHQNQODAZ
  • [K]OS(=O)(=O)O[Cr]1OS(=O)(=O)O1
Properties
KCr(SO4)2
Molar mass 283.220 g/mol
Appearance dark purple needles or greyish-brown powder when anhydrous
Density 1.83 g cm−3
Melting point 89 °C (192 °F; 362 K)
Boiling point 400 °C (752 °F; 673 K)
24 g/100mL (at 20 °C)
Hazards
GHS labelling:
GHS07: Exclamation mark
Warning
H315, H319
P305+P351+P338
Structure
cubic
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Chrome alum or Chromium(III) potassium sulfate is the potassium double sulfate of chromium. Its chemical formula is KCr(SO4)2 and it is commonly found in its dodecahydrate form as KCr(SO4)2·12(H2O). It is used in leather tanning.[1]

  1. ^ Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). "Chromium". Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 1082–1095. ISBN 3-11-007511-3.