Phases and Structures of Aluminum Hydride

As previously discussed, non-solvated A1H3 was prepared by Brower et al. [15], who reported the existence of at least 7 nonsolvated phases, namely a, a, (3, y, S, e, and However only a-, a -, (3-, and y-phases have been synthesized reproducibly, in contrast to the other structures that may have been identified as a result of impurities. 

Ke et al. conducted a study on the structural properties of AIH3 using density functional theory (DPT) methods [45]. They reported that the a -(orthorhombic) and (3-(cubic) modifications are more stable than a-(hexagonal) at 0 K (no phonons). The finding is, however, in contrast to experimental results, which have shown that the a-crystalline phase is the most stable phase at ambient conditions. 

The P-AID3 structure contains corner-sharing AlD octahedra, similar to the a- and the a -phases. It should be noted that a high purity P-AID3 sample is difficult to prepare [15]. However, the P-AID3 sample studied by Brinks et al. was considered to 

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