Chromium(III) sulfate

Chromium(III) sulfate ;
Names:	chromium(III) sulfate; chromium trisulfate;
Formula:	Cr2(SO4)3 (anhydrous); Cr2(SO4)3 · 18H2O (octadecahydrate);
Molar mass:	392.175 g/mol (anhydrous); 716.443 g/mol (octadecahydrate);
Density:	1.709 g/cm3 (octadecahydrate); 1.867 g/cm3 (pentadecahydrate); 3.012 g/cm3 (anhydrous);
Crystal system:	rhombohedral (anhydrous); a=8.143 Å, b=8.143 Å, c=8.143 Å;
Shapes:	https://en.crystalls.info/w/uploads/media/b/bc/Rhombic_prism.json Rhombic prism ;
Color:	dark-violet; dark-green;
Melting point:	90 °C363.15 K <br />194 °F <br />653.67 °R <br /> (octadecahydrate);
Decomposition point:	100 °C373.15 K <br />212 °F <br />671.67 °R <br /> (octadecahydrate); 700 °C973.15 K <br />1,292 °F <br />1,751.67 °R <br /> (anhydrous);
Refractive index:	1.564 (octadecahydrate);
Magnetic properties:	paramagnetic; χ=1.18 · 10-1cm³/mol;
Stability:	hygroscopic (octadecahydrate)

Description

Inorganic compound, salt of transitional metal chromium and inorganic sulfuric acid. From water solutions crystallizes as octadecahydrate.

Influence of temperature

The color of solution depends on the temperature - hot solution is green, cold is violet.

Influence of impurities

Can produce adducts with sulfuric acid.

Notes

In most cases, solution becomes a viscous syrup which doesn't produce any crystals, even with addition of ethanol.

Solubility

TableGraph

Temperature	g/`100,00` g water
Temperature	(anhydrous)	(octadecahydrate)
20°C293.15 K <br />68 °F <br />527.67 °R <br />	`64`	`120`

Slightly soluble in ethanol. Insoluble in ethyl acetate and methylamine.

Gallery

Sources

Sulfates
Simple	Aluminum sulfate (Al₂(SO₄)₃) • Ammonium sulfate ((NH₄)₂SO₄) • Calcium sulfate (CaSO₄) • Cadmium sulfate (CdSO₄) • Cerium(III) sulfate (Ce₂(SO₄)₃) • Cerium(IV) sulfate (Ce(SO₄)₂) • Chromium(III) sulfate (Cr₂(SO₄)₃) • Cobalt(II) sulfate (CoSO₄) • Copper(II) sulfate (CuSO₄) • Gadolinium sulfate (Gd₂(SO₄)₃) • Holmium sulfate (Ho₂(SO₄)₃) • Hydrazine sulfate (N₂H₄ · H₂SO₄) • Iron(II) sulfate (FeSO₄) • Iron(III) sulfate (Fe₂(SO₄)₃) • Lanthanum sulfate (La₂(SO₄)₃) • Lithium sulfate (Li₂SO₄) • Magnesium sulfate (MgSO₄) • Manganese(II) sulfate (MnSO₄) • Neodymium sulfate (Nd₂(SO₄)₃) • Nickel sulfate (NiSO₄) • Potassium sulfate (K₂SO₄) • Praseodymium(III) sulfate (Pr₂(SO₄)₃) • Rubidium sulfate (Rb₂SO₄) • Sodium hydrosulfate (NaHSO₄) • Sodium sulfate (Na₂SO₄) • Yttrium sulfate (Gd₂(SO₄)₃) • Zinc sulfate (ZnSO₄)
Alums	Aluminum-ammonium sulfate (NH₄Al(SO₄)₂) • Aluminum-potassium sulfate (KAl(SO₄)₂) • Chromium(III)-ammonium sulfate (NH₄Cr(SO₄)₂) • Chromium(III)-potassium sulfate (KCr(SO₄)₂) • Cobalt(III)-ammonium sulfate (NH₄Co(SO₄)₂) • Indium(III)-potassium sulfate (KIn(SO₄)₂) • Iron(III)-ammonium sulfate (NH₄Fe(SO₄)₂) • Iron(III)-potassium sulfate (KFe(SO₄)₂) • Manganese(III)-ammonium sulfate (NH₄Mn(SO₄)₂) • Vanadium(III)-ammonium sulfate (NH₄V(SO₄)₂)
Tutton's salts	Chromium(II)-ammonium sulfate ((NH₄)₂Cr(SO₄)₂) • Cobalt(II)-ammonium sulfate ((NH₄)₂Co(SO₄)₂) • Cobalt(II)-potassium sulfate (K₂Co(SO₄)₂) • Copper(II)-ammonium sulfate ((NH₄)₂Cu(SO₄)₂) • Copper(II)-potassium sulfate (K₂Cu(SO₄)₂) • Iron(II)-ammonium sulfate ((NH₄)₂Fe(SO₄)₂) • Iron(II)-potassium sulfate (K₂Fe(SO₄)₂) • Magnesium-ammonium sulfate ((NH₄)₂Mg(SO₄)₂) • Magnesium-potassium sulfate (K₂Mg(SO₄)₂) • Magnesium-potassium sulfate-chromate (K₂CrO₄ · MgSO₄) • Manganese(II)-ammonium sulfate ((NH₄)₂Mn(SO₄)₂) • Manganese(II)-potassium sulfate (K₂Mn(SO₄)₂) • Nickel-ammonium sulfate ((NH₄)₂Ni(SO₄)₂) • Nickel-potassium sulfate (K₂Ni(SO₄)₂) • Vanadium(II)-ammonium sulfate ((NH₄)₂V(SO₄)₂) • Zinc-ammonium sulfate ((NH₄)₂Zn(SO₄)₂) • Zinc-potassium sulfate (K₂Zn(SO₄)₂)
Double salts	Copper(II)-iron(II) sulfate ((Cu,Fe)SO₄) • Iron(II)-magnesium sulfate ((Fe,Mg)SO₄) • Lithium-potassium sulfate (KLiSO₄) • Sodium-ammonium sulfate (NaNH₄SO₄) • Zinc-sodium sulfate (Na₂Zn(SO₄)₂)
Adducts	Triglycine sulfate ((NH₂CH₂COOH)₃ · H₂SO₄) • Glutamic acid sulfate (C₅H₉NO₄ · H₂SO₄)
Complexes	Cerium(III) sulfocerate(IV) (Ce₄[Ce(SO₄)₄]₃) • Glycinecopper(II) sulfate ([Cu(NH₂CH₂COOH)]SO₄) • Hexakarbamatzinc sulfate ([(CON₂H₄)₆Zn]SO₄) • Tetraamminecopper(II) sulfate ([Cu(NH₃)₄]SO₄) • Tris(hydroxymethil)methanoaminecopper(II) sulfate ([Cu(NH₂C(CH₂OH)₃)₄]SO₄)

Chromium compounds
Salts	Chromates • Chromium(II) acetate (Cr(CH₃COO)₂) • Chromium(III) sulfate (Cr₂(SO₄)₃) • Chromium(II)-ammonium sulfate ((NH₄)₂Cr(SO₄)₂) • Chromium(III)-ammonium sulfate (NH₄Cr(SO₄)₂) • Chromium(III)-potassium sulfate (KCr(SO₄)₂)
Complexes	Hexacyanochromates • Trioxalatochromates

Chromium(III) sulfate
Names:	chromium(III) sulfate chromium trisulfate
Formula:	Cr₂(SO₄)₃ (anhydrous) Cr₂(SO₄)₃ · 18H₂O (octadecahydrate)
Molar mass:	392.175 g/mol (anhydrous) 716.443 g/mol (octadecahydrate)
Density:	1.709 g/cm³ (octadecahydrate) 1.867 g/cm³ (pentadecahydrate) 3.012 g/cm³ (anhydrous)
Crystal system:	rhombohedral (anhydrous) a=8.143 Å, b=8.143 Å, c=8.143 Å
Shapes:	Rhombic prism
Color:	dark-violet dark-green
Melting point:	90 °C363.15 K <br />194 °F <br />653.67 °R <br /> (octadecahydrate)
Decomposition point:	100 °C373.15 K <br />212 °F <br />671.67 °R <br /> (octadecahydrate) 700 °C973.15 K <br />1,292 °F <br />1,751.67 °R <br /> (anhydrous)
Refractive index:	1.564 (octadecahydrate)
Magnetic properties:	paramagnetic χ=1.18 · 10^-1cm³/mol
Stability:	hygroscopic (octadecahydrate)