Formation of interstitial compounds

When small atoms like hydrogen, carbon or nitrogen are trapped in the interstitial spaces within the crystal lattice, the compounds formed are called interstitial compounds. Sometimes sulphides and oxides are also trapped in the crystal lattice of transition elements. Steel and cast iron are examples of interstitial compounds of carbon and iron. Due to the presence of carbon, the malleability and ductility of iron is reduced, while its tenacity increases.

Some properties of interstitial compounds

• i. They are hard and good conductors of heat and electricity.
• ii. Their chemical properties are similar to the parent metal.
• iii. Their melting points are higher than the pure metals.
• iv. Their densities are less than the parent metal.
• v. The metallic carbides are chemically inert and extremely hard as diamond. …