Reactions of lithium hydride and beryllium hydride: thermal studies and identification of products

Using simultaneous differential thermal analysis and thermogravimetric analysis, and powder X-ray diffraction, we determined that the reactions of lithium hydride and beryllium hydride follow the pathway for reaction mixtures containing less than 66.6 mol.% LiH, and for reaction mixtures containing 66.6 mol.% LiH or more. LiBeH3 undergoes fusion at 430 K. Li2BeH4 has two thermal transitions at 550 K and 660 K; the first may be intramolecular rearrangement and the second may be fusion. The two products are indistinguishable by powder X-ray diffraction.