Question

What is meant by complex compound? Describe the main points of Werner's theory.

Answer 1

Coordination compound, any of a class of substances with chemical structures in which a central metal atom is surrounded by nonmetal atoms or groups of atoms, called ligands, joined to it by chemical bonds.

Werner theory describes the structure and formation of complex compounds or coordination compounds.

Main points of Werner’s Theory:

1.The central metal or the metal atoms in coordination compounds show two types of valency. They are the primary and the secondary valency.

2. The primary valency relates to the oxidation state and the secondary valency relates to the coordinate number.

3. The number of secondary valences is fixed for every metal atom. It means that the coordination number is fixed.

4. The metal atom works towards satisfying both its primary and secondary valencies. A negative ion satisfies the primary valency. On the other hand, a negative ion or neutral molecules satisfy secondary valencies.

5. The secondary valencies point towards a fixed position in space thus have definite geometry of the compound thus its directional.