Solid State - Result Question 4
####4. The statement that is incorrect about the interstitial compounds is
(2019 Main, 8 April II)
(a) they are very hard
(b) they have metallic conductivity
(c) they have high melting points
(d) they are chemically reactive
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Answer:
Correct Answer: 4. (d)
Solution:
- Interstitial compounds are formed when a neutral atom with a small radius occupies in an interstitial hole (tetrahedral or octahedral voids) in a transition metal’s hcp or ccp lattices (host lattice). Examples of small atoms (guest atom) are H, B, C and $N$.
Interstitial compounds are non-stoichiometric (Birtholide) in composition. They are very hard with very high melting points. The electrical conductivity of interstitial compounds are comparable to that of the pure metal. These are chemically unreactive in nature.
