Why are Ionic Hydrides more denser?

[zorro]

Why do ionic hydrides have more density than the corresponding metals?
I know that interstitial hydrides have lower density than the corresponding metals from which they were formed as the crystal lattice expands due to inclusion of H₂. What makes ionic hydrides more denser then?

 

[lightarrow]

Why do ionic hydrides have more density than the corresponding metals?
I know that interstitial hydrides have lower density than the corresponding metals from which they were formed as the crystal lattice expands due to inclusion of H₂. What makes ionic hydrides more denser then?

It depends on which metals. Ionic hydrides are formed with metals of the I or II group, usually, and these metals have a low density because of their great metallic radius (at similar atomic weight), compared with other metals. In a ionic compound, these metals leave their valence electrons becaming low radius ions. Added with the fact that H- ion has a low radius too...

 

[zorro]

Thanks lightarrow!