Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds? 

1. They have high melting points in comparison to pure metals
2. They are very hard
3. They are conductor.
4. They are chemically very reactive



Hint: Interstitial compounds are those which are formed when small atoms like H, C or N are trapped inside the crystal lattices of metals.

Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Their important characteristics are as follows:
(i) They are very hard and rigid.
(ii), They have a high melting point which is higher than those of the pure metals.
(iii) They are also a conductor like metal
(iv) They acquire chemical inertness.