Syntheses, crystal structures, and thermal analyses of solvent-free Ca(AlD4)2 and CaAlD5

Crystal Structural Determination of SrAlD5 with Corner-Sharing AlD6 Octahedron Chains by X-ray and Neutron Diffraction

“…Al originated from AlD 3 decomposition or the mechanochemical milled SrD 2 + 2AlD 3 since the presence of a complex anion, [AlD 4 ] -, in the mechanochemical milled sample was identified by Raman spectroscopy. This confirms that Sr(AlD 4 ) 2 could be obtained from mechanochemical milling of SrD 2 + 2AlD 3 as reported in previous works [8,10,17] although the crystal structure of Sr(AlD 4 ) 2 could not be determined due to its poor crystallinity. The remaining Bragg peaks were indexed by an orthorhombic unit cell with a ≈ 4.66 Å, b ≈ 12.71 Å and c ≈ 5.03 Å, and these values are close to the theoretically and experimentally reported unit cell parameters of SrAlH 5 [7,11].…”

“…under a deuterium gas pressure of 0.3 MPa using a Fritsch P7. The effective milling time was 3 h. Milling times of 15 min were alternated with pauses of 5 min duration, similar to our previous study [8,10,17].…”

“…Interestingly, alkaline-earth metal tetra-alanates M(AlH 4 ) 2 composed of an alkaline-earth metal (M) and [AlH 4 ] − decompose into MAlH 5 containing corner-sharing AlH 6 octahedron chains [3,[6][7][8][9] after releasing hydrogen from M(AlH 4 ) 2 (Equation (2)). We refer to MAlH 5 as an alkaline-earth metal penta-alanate.…”

“…Therefore, the corner-sharing AlH 6 octahedron chains are a unique feature of alanates composed of alkaline-earth metals. Although the crystal structures of CaAlH 5 [6][7][8] and BaAlH 5 [9] have been experimentally and theoretically identified, the structures of BeAlH 5 , MgAlH 5 and SrAlH 5 have so far not been experimentally proven. BeAlH 5 and MgAlH 5 may be difficult to form due to the small size of Be 2+ and Mg 2+ .…”

Metal aluminum amides for hydrogen storage – Crystal structure studies

“…respectively, as a function of effective ionic radii of the metal [43]. For the alanates, larger cation results in a longer cation-D distance [42], which is also the case for the cation-N distances in aluminum amides. These distances show linear correlation with effective ionic radii.…”