State-of-the-art electronic structure calculations provide the likelihood of the availability of AlLi2MgHn, ScLi2MgHn, TiLi2MgHn, VLi2MgHn, CrLi2MgHn, MnLi2MgHn, FeLi2MgHn, CoLi2MgHn, NiLi2MgHn, CuLi2MgHn, ZnLi2MgHn, GaLi2MgHn, GeLi2MgHn, PdLi2MgHn, AgLi2MgHn, CdLi2MgHn, InLi2MgHn, SnLi2MgHn, SbLi2MgHn, PtLi2MgHn, AuLi2MgHn, HgLi2MgHn, TlLi2MgHn, PbLi2MgHn, and BiLi2MgHn (here n is an integer having a value in a particular compound of 4-7) as solid hydrides for the storage and release of hydrogen. Different hydrogen contents may be obtained in compounds having the same XLi2Mg crystal structures. These materials offer utility for hydrogen storage systems.