Metallic hydrides -

Metallic hydrides are those compounds which are formed when transition element react with hydrogen. Eg. CaH₂ , LiBH₄

Molecular Hydrides -

Molecular hydrides are formed by the combination of an element which is having comparable higher electronegativity with hydrogen. Eg. H₂O , B₂H₆

Metal hydrides have high thermal and electrical conductivity whereas the molecular hydrides have low thermal and electrical conductivity.

Metallic hydrides are found in solid state whereas the molecular hydrides are comparatively soft & volatile.