CaAlH5 crystallizes in the orthorhombic P2_12_12_1 space group. Ca(1) is bonded in a 11-coordinate geometry to one H(3), two equivalent H(1), two equivalent H(2), three equivalent H(4), and three equivalent H(5) atoms. Al(1) is bonded to one H(1), one H(2), one H(4), one H(5), and two equivalent H(3) atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are five inequivalent H sites. In the first H site, H(1) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Al(1) atom. In the second H site, H(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Al(1) atom. In the third H site, H(3) is bonded in a 3-coordinate geometry to one Ca(1) and two equivalent Al(1) atoms. In the fourth H site, H(4) is bonded in a 1-coordinate geometry to three equivalent Ca(1) and one Al(1) atom. In the fifth H site, H(5) is bonded in a distorted single-bond geometry to three equivalent Ca(1) and one Al(1) atom.
CaAlH5 crystallizes in the orthorhombic P2_12_12_1 space group. Ca(1) is bonded in a 11-coordinate geometry to one H(3), two equivalent H(1), two equivalent H(2), three equivalent H(4), and three equivalent H(5) atoms. The Ca(1)-H(3) bond length is 2.47 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Ca(1)-H(1) bond length. There is one shorter (2.30 Å) and one longer (2.38 Å) Ca(1)-H(2) bond length. There are a spread of Ca(1)-H(4) bond distances ranging from 2.38-2.65 Å. There are a spread of Ca(1)-H(5) bond distances ranging from 2.44-2.61 Å. Al(1) is bonded to one H(1), one H(2), one H(4), one H(5), and two equivalent H(3) atoms to form corner-sharing AlH6 octahedra. The corner-sharing octahedral tilt angles are 43°. The Al(1)-H(1) bond length is 1.69 Å. The Al(1)-H(2) bond length is 1.71 Å. The Al(1)-H(4) bond length is 1.71 Å. The Al(1)-H(5) bond length is 1.74 Å. There is one shorter (1.75 Å) and one longer (1.79 Å) Al(1)-H(3) bond length. There are five inequivalent H sites. In the first H site, H(1) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Al(1) atom. In the second H site, H(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Al(1) atom. In the third H site, H(3) is bonded in a 3-coordinate geometry to one Ca(1) and two equivalent Al(1) atoms. In the fourth H site, H(4) is bonded in a 1-coordinate geometry to three equivalent Ca(1) and one Al(1) atom. In the fifth H site, H(5) is bonded in a distorted single-bond geometry to three equivalent Ca(1) and one Al(1) atom.