Theoretical exploration of hydrogen loss from AlH 3 and Al 2 H 6

Quantum chemistry calculations are used to explore H 2 loss from AlH 3 and Al 2 H 6 and provide insight into the hydrogen production mechanism from polyalanes, a candidate material for energy storage. We present optimized structures for AlH 3 , Al 2 H 4 , Al 2 H 5 , and Al 2 H 6 and some reaction pathways for their interconversion. We have found two pathways for the reaction Al 2 H 6 → Al 2 H 4 + H 2 , which have activation barriers lower in energy than for the removal of H 2 from AlH 3 . However, the low‐energy H 2 loss pathway from Al 2 H 6 suggests that the noninteracting Al–H bonds in the transition state structure favor having bonding similar to that occurring in AlH 3 . © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010