Due to its chemical character, and contrary to Aluminium, Iron can form bi- and tri-valent salts. The bivalent salts are widely used as a raw material for producing the trivalent products but can be applied directly as well.

Bivalent

• Ferrous sulphate heptahydrate solid FeSO₄ x 7 H₂O.  
  It’s commonly known as “Copperas”, “Iron Vitriol” or “Green Vitriol”.  This green salt has a physical property like wet snow. It is difficult to store but very easy to dissolve.
• Ferrous sulphate monohydrate solid FeSO₄ x  H₂O.
  This is dehydrated and dried copperas. It is a light grey free flowing powder which can be stored in silo and be conveyed by a screw or pneumatically.
• Ferrous chloride aqueous solution, 20%-30%.
  The solutions are light to dark green but clear liquids.

Trivalent

• Ferric sulphate solid, Fe₂(SO₄)₃
  A dark yellow powder with slightly hygroscopic properties.
• Ferric sulphate aqueous solution,                                                                                                                                                                                     Fe₂(SO₄)₃ , 35% - 40%
  A dark brown solution with a relatively high viscosity.
• Ferric chloride aqueous solution, FeCl₃  32% - 45 %.
  Brown solution with excellent stability and easy to store.
• Ferric chloride sulphate aqueous solution, FeClSO₄  38% - 41%
  Like all Ferric salts a brownish solution as well.