All the alkali earth metals, except beryllium combine with hydrogen upon heating to form their hydrides,${\mathrm{MH}}_2$. ${\mathrm{BeH}}_2$, however, can be prepared by the reaction of ${\mathrm{BeCl}}_2$ with ${\mathrm{LiAlH}}_4$. .

$2{\mathrm{BeCl}}_2+{\mathrm{LiAlH}}_4\to 2{\mathrm{BeH}}_2+\mathrm{LiCl}+{\mathrm{AlCl}}_3$