Coordination Compounds – Notes

Introduction

When two or more stable compounds are allowed to evaporate or to combine in stoichiometric ratios, crystalline addition or molecular compounds are formed.

Double salts are molecular compounds that are stable in the solid state, but break down into individual constituents when dissolved in water. The individual properties of the constituents are not lost.

Coordination compounds are molecular compounds that do not dissociate into ions and retain their identities even when dissolved in water. The individual properties of the constituents are lost.

Compounds that have complex ions are called complex compounds.

Chlorophyll is a coordination complex of magnesium, haemoglobin of iron, and vitamin B₁₂ of cobalt.

Complex compounds find extensive use in electroplating, metallurgical processes, textile dyeing and medicinal chemistry, and as industrial catalysts and analytical reagents.