What are interstitial compounds? Why are such compounds well known for the transition metals?

What are interstitial compounds? Why are such compounds well known for transition metals?

What are the interstitial compounds ? Why are such compounds well known for transition metals ?

(a) Why are Mn^(2+) compounds more stable than Fe^(2+) towards oxidation to their +3 state. (b) What are interstitial compounds ? Why are such compounds well-known for transition metals ? (c ) Write electronic configuration of Pm^(3+)

What interstitial compounds?

Why are interstitial compounds well known for transition elements ?