Interstitial compounds are chemically inert but retain their metallic ocnductivity. 

Explian why.

Dear Student,

An interstitial compound is a compound that is formed when an atom of sufficiently small radius such as hydrogen, carbon, boron and nitrogen sits in an interstitial “hole” in a metal lattice.

The metal lattice is relatively unaffected by the interstitial atom and electrical conductivity is comparable to that of the pure metal.This is because in many metal hydrides, the ratio of metal atoms to the hydrogen atoms is not a simple whole number ratio nor it is fixed ratio. The composition can vary within a range, depending upon the conditions of synthesis. They may be considered to be solutions of hydrogen atoms in metal, with hydrogen atoms occupying the holes or interstices between metal atoms in the solid lattice. So metallic conductivity remains unaffected.

Hope it answers your query.