Answer:
1. An interstitial compound or alloy is a compound that is formed when small atoms like hydrogen, boron, carbon or nitrogen are trapped in the interstitial holes in a metal lattice. 2. They are usually non-stoichiometric compounds. 3. Transition metals form a number of interstitial compounds such as TiC, ZrH1.92 , Mn4N etc. 4. The elements that occupy the metal lattice provide them new properties. They are hard and show electrical and thermal conductivity They have high melting points higher than those of pure metals Transition metal hydrides are used as powerful reducing agents Metallic carbides are chemically inert