Complex salts and double salts

Complex Salts and Double Salts

In inorganic chemistry, when two or more simple salts combine, they can give rise to two main types of compounds: complex salts and double salts. While both result from mixing different salts, they show notable differences in structure and behavior when dissolved in water.

1. Double Salts

Double salts are produced by the union of two distinct simple salts in a definite, fixed ratio by weight or moles. These salts exist only in the solid state and dissociate completely into their constituent ions when dissolved in water.

Characteristics of Double Salts:

• They dissociate into all of their constituent ions in aqueous solution.
• They dissociate completely in solution and do not maintain their individual structure.
• They exhibit the properties of all individual ions present.

Examples of Double Salts:

• Mohr’s Salt – FeSO₄·(NH₄)₂SO₄·6H₂O
• Potash Alum – K₂SO₄·Al₂(SO₄)₃·24H₂O
• Carnallite – KCl·MgCl₂·6H₂O

2. Complex Salts

Complex salts are compounds that contain a central metal ion bonded to one or more ligands (ions or molecules), forming a coordination complex. Unlike double salts, complex salts retain their molecular identity in solution.

Characteristics of Complex Salts:

• They do not dissociate completely into their constituent ions in solution.
• They form a stable coordination entity (complex ion).
• They exhibit properties specific to the complex ion rather than individual components.

Examples of Complex Salts:

• Potassium ferrocyanide – K₄[Fe(CN)₆]
• Diamminesilver(I) chloride – [Ag(NH₃)₂]Cl
• Tetraamminecopper(II) sulfate – [Cu(NH₃)₄]SO₄

Major Distinctions Between Complex Salts and Double Salts: