Iron(III) sulfate

Iron(III) sulfate (or ferric sulfate), is the chemical compound with the formula Fe₂(SO₄)₃. Usually yellow, it is a salt and soluble in water. A variety of hydrates are also known. Solutions are used in dyeing as a mordant, and as a coagulant for industrial wastes. It is also used in pigments, and in pickling baths for aluminum and steel.[2][3]

Iron(III) sulfate

Names
IUPAC name Iron(III) sulfate
Other names Ferric sulfate Sulfuric acid, iron(3+) salt (3:2)
Identifiers
CAS Number	10028-22-5
3D model (JSmol)	Interactive image
ChEBI	CHEBI:53438
ChemSpider	23211
ECHA InfoCard	100.030.054
PubChem CID	24826
RTECS number	NO8505000
UNII	4YKQ1X5E5Y
CompTox Dashboard (EPA)	DTXSID5029712
InChI InChI=1S/2Fe.3H2O4S/c;;3*1-5(2,3)4/h;;3*(H2,1,2,3,4)/q2*+3;;;/p-6 Key: RUTXIHLAWFEWGM-UHFFFAOYSA-H InChI=1/2Fe.3H2O4S/c;;3*1-5(2,3)4/h;;3*(H2,1,2,3,4)/q2*+3;;;/p-6 Key: RUTXIHLAWFEWGM-CYFPFDDLAR
SMILES [Fe+3].[Fe+3].[O-]S(=O)(=O)[O-].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O
Properties
Chemical formula	Fe2(SO4)3
Molar mass	399.88 g/mol (anhydrous) 489.96 g/mol (pentahydrate) 562.00 g/mol (nonahydrate)
Appearance	grayish-white crystals
Density	3.097 g/cm^3 (anhydrous) 1.898 g/cm^3 (pentahydrate)
Melting point	480 °C (896 °F; 753 K) (anhydrous) 175 °C (347 °F) (nonahydrate)
Solubility in water	256g/dm^3 (monohydrate, 293K)
Solubility	sparingly soluble in alcohol negligible in acetone, ethyl acetate insoluble in sulfuric acid, ammonia
Refractive index (nD)	1.814 (anhydrous) 1.552 (nonahydrate)
Hazards
NFPA 704 (fire diamond)	0 1 0
Lethal dose or concentration (LD, LC):
LD50 (median dose)	500 mg/kg (oral, rat)
NIOSH (US health exposure limits):
REL (Recommended)	TWA 1 mg/m^3[1]
Related compounds
Other anions	Iron(III) chloride Iron(III) nitrate
Related compounds	Iron(II) sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Production

Generally, ferric sulfate is used as a solution generated from iron wastes. The actual speciation is vague but its applications do not demand high purity materials.

Iron(III) sulfate is often generated as a solution rather than being isolated as a solid. It is produced on a large scale by treating sulfuric acid, a hot solution of ferrous sulfate, and an oxidizing agent. Typical oxidizing agents include chlorine, nitric acid and hydrogen peroxide.[4]

2 FeSO₄ + H₂SO₄ + H₂O₂ → Fe₂(SO₄)₃ + 2 H₂O

Natural occurrences

Mikasaite, a mixed iron-aluminium sulfate of chemical formula (Fe³⁺, Al³⁺)₂(SO₄)₃[5] is the name of mineralogical form of iron(III) sulfate. This anhydrous form occurs very rarely and is connected with coal fires. The hydrates are more common, with coquimbite (nonahydrate) as probably the most often met among them. Paracoquimbite is the other, rarely met natural nonahydrate. Kornelite (heptahydrate) and quenstedtite (decahydrate) are rarely found. Lausenite (hexa- or pentahydrate) is a doubtful species. All the mentioned natural hydrates are unstable compounds connected with Fe-bearing primary minerals (mainly pyrite and marcasite) oxidation in ore beds. In the solutions of the ore beds oxidation zones the iron(III) sulfate is also an important oxidative agent.

Coquimbite crystal structure

See also

• Iron(II) sulfate
• Ammonium iron(II) sulfate
• Ammonium iron(III) sulfate

References

1. NIOSH Pocket Guide to Chemical Hazards. "#0346". National Institute for Occupational Safety and Health (NIOSH).
2. Ferric sulfate. The Columbia Encyclopedia, Sixth Edition. Retrieved November, 2007.
3. Wildermuth, Egon; Stark, Hans; Friedrich, Gabriele; Ebenhöch, Franz Ludwig; Kühborth, Brigitte; Silver, Jack; Rituper, Rafael (2000). "Iron Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a14_591.
4. Iron compounds. Encyclopædia Britannica Article. Retrieved November, 2007
5. Mikasaite

External links

• Material Safety Data Sheet