Question

Interstitial compounds are not formed by :

• A. Co
• B. Ni
• C. Fe
• D. Ca

Answer 1

Answer: (D)

D

Answer 2

Interstitial compounds are typically formed by transition metals. These metals have appropriate atomic sizes and crystal structures with voids (interstitial sites) that can accommodate small non-metal atoms like H, B, C, N. This leads to the formation of non-stoichiometric compounds with characteristic properties.

Calcium is an alkaline earth metal (s-block element). Alkaline earth metals generally do not form interstitial compounds. Their atomic structure and bonding characteristics are different from transition metals, and their crystal lattices do not typically provide suitable interstitial sites for the formation of stable interstitial compounds. They primarily form ionic compounds.