Coordination Preference of Ga in Hydrides

Aluminum and gallium show some interesting differences in their coordination chemistry. Solid GaH3 is unknown,
in contrast to solid AlH3. Ga equivalents of Li3AlH6, Na3AlH6, and other hydrides whose structure contain AlH6 3-
ions, are unknown. We relate these differences to an instability of the hexacoordinated gallium moiety.