`BeH_(2)` cannot be prepared directly by heating powdered beryllium with dihydrogen . It can , however , be prepared from the corresponding halides by reduction with complex alkali metal hydrides such as lithium aluminium hydride as follows .
`8 LiH + Al_(2) Cl_(6) to 2 LiAlH_(4) + 6 LiCl`
`2 BeCl_(2) + LiAlH_(4) to 2 BeH_(2) + LiCl + AlCl_(3)`.