Which of the following is/are true about interstitial compounds:

The correct options are
A Interstitial compounds have the same chemical properties as that of the parent metal.
C As a result of filling up of interstitial spaces, these compounds becomes rigid and hard.
D Interstitial compounds have higher melting points which are higher than those of pure metals.
Interstitial compounds have the same chemical properties as that of the parent metal but differ in physical properties (density, conductivity, hardness) as compared to that of the parent metal. As a result of filling up of interstitial spaces the metals becomes rigid and hard, thus they have higher melting points which are higher than those of pure metals.