What characteristics do you expect from electrondeficient hydrides with respect to their structure and chemical reactivity?

Explanation

Electron-deficient hydrides have less number of electrons in the valence shell of the central atom and so, their mononuclear units do not satisfy the usual Lewis octet rule. Due to deficiency of electrons, these hydrides act as Lewis acids and form complex entities with Lewis bases such as `NH_(3), H^(-)` ion etc.
`B_(2)H_(6) + 2NH_(3) rarr [BH_(2)(NH_(3))_(2)]^(+)[BH_(4)]^(-)` ,
`B_(2)H_(6) + 2LiH rarr 2Li^(+)[BH_(4)]^(-)` (Lithium borohydride)