Ammonium Ferric Sulphate

Ammonium ferric sulfate, with the chemical formula NH₄Fe(SO₄)₂·12H₂O, is a fascinating compound with a variety of applications. Here's a more in-depth look:

Chemical Properties and Characteristics:

• Double Salt:
  • It's a double salt, meaning it contains two different cations (ammonium and iron) and a common anion (sulfate).
  • It belongs to the class of compounds known as alums, which have the general formula AB(SO₄)₂·12H₂O.
• Appearance:
  • It typically appears as pale violet, octahedral crystals. The subtle violet hue has been a subject of scientific discussion, with explanations ranging from inherent crystal properties to the presence of trace impurities.
• Solubility:
  • It is highly soluble in water.
• Chemical Behavior:
  • It's paramagnetic, meaning it's weakly attracted to magnetic fields.
  • It forms acidic solutions in water.
  • It exhibits oxidizing properties, though it's considered a weak oxidizing agent.
  • it can be reduced to Mohr's salt, ferrous ammonium sulfate.

Applications:

• Water Treatment:
  • It's used as a coagulant in water and wastewater treatment, helping to remove suspended solids and impurities.
• Dyeing:
  • It serves as a mordant in textile dyeing, fixing dyes to fabrics.
• Chemical Analysis:
  • It's employed in various analytical chemistry applications.
• Other Uses:
  • It has applications in etching for electronic components.
  • It is used in biochemical analysis.
  • It is used in organic synthesis.

Preparation:

• Ammonium ferric sulfate is typically prepared by crystallizing a solution containing ferric sulfate and ammonium sulfate.
• The iron(II) in ferrous sulphate is oxidized to ferric sulphate by the addition of sulphuric and nitric acid. Then by the addition of ammonium sulphate, the ferric ammonium sulphate is crystallized.

Safety Considerations:

• It can be an irritant to the skin and eyes.
• Appropriate safety precautions should be taken when handling this chemical.