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AlH6 is Cyanogen Chloride-derived structured and crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four $l^{2}-alumane molecules and twelve hydrogen molecules.
K2LiAlH6 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve H1- atoms to form KH12 cuboctahedra that share corners with nine KH12 cuboctahedra, corners with three equivalent LiH6 octahedra, faces with seven KH12 cuboctahedra, faces with three equivalent LiH6 octahedra, and faces with four AlH6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are a spread of K–H bond distances ranging from 2.82–2.86 Å. In the second K1+ site, K1+ is bonded to twelve H1- atoms to form KH12 cuboctahedra that share corners with nine KH12 cuboctahedra, corners with three equivalent AlH6 octahedra, faces with seven KH12 cuboctahedra, faces with three equivalent AlH6 octahedra, and faces with four equivalent LiH6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of K–H bond distances ranging from 2.83–2.90 Å. Li1+ is bonded to six H1- atoms to form LiH6 octahedra that share corners with three equivalent KH12 cuboctahedra, corners with three equivalent AlH6 octahedra, faces with seven KH12 cuboctahedra, and a faceface with one AlH6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are three shorter (2.01 Å) and three longer (2.04 Å) Li–H bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 octahedra and faces with eight KH12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. All Al–H bond lengths are 1.79 Å. In the second Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent KH12 cuboctahedra, faces with six equivalent KH12 cuboctahedra, and faces with two equivalent LiH6 octahedra. All Al–H bond lengths are 1.77 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted linear geometry to four K1+, one Li1+, and one Al3+ atom. In the second H1- site, H1- is bonded in a distorted L-shaped geometry to four K1+, one Li1+, and one Al3+ atom.
LiMgAlH6 is Hydrophilite-derived structured and crystallizes in the trigonal P321 space group. The structure is three-dimensional. Li1+ is bonded to six H1- atoms to form LiH6 octahedra that share corners with two equivalent AlH6 octahedra, corners with six equivalent MgH6 octahedra, and edges with two equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 52–55°. There are a spread of Li–H bond distances ranging from 1.86–1.99 Å. Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with four equivalent AlH6 octahedra, corners with six equivalent LiH6 octahedra, and an edgeedge with one AlH6 octahedra. The corner-sharing octahedra tilt angles range from 48–55°. There are a spread of Mg–H bond distances ranging from 1.92–1.99 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 octahedra and edges with three equivalent MgH6 octahedra. The corner-sharing octahedral tilt angles are 53°. All Al–H bond lengths are 1.74 Å. In the second Al3+ site, Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with six equivalent MgH6 octahedra and edges with three equivalent LiH6 octahedra. The corner-sharing octahedra tilt angles range from 48–50°. All Al–H bond lengths are 1.75 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a trigonal planar geometry to one Li1+, one Mg2+, and one Al3+ atom. In the second H1- site, H1- is bonded in a distorted trigonal planar geometry to one Li1+, one Mg2+, and one Al3+ atom. In the third H1- site, H1- is bonded in a trigonal planar geometry to one Li1+, one Mg2+, and one Al3+ atom.
Na5Al3H14 crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a body-centered cubic geometry to eight equivalent H1- atoms. All Na–H bond lengths are 2.50 Å. In the second Na1+ site, Na1+ is bonded to six H1- atoms to form distorted NaH6 octahedra that share corners with two equivalent NaH6 octahedra, corners with six AlH6 octahedra, and edges with four equivalent NaH6 octahedra. The corner-sharing octahedra tilt angles range from 38–71°. There are a spread of Na–H bond distances ranging from 2.22–2.55 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with four equivalent AlH6 octahedra and corners with eight equivalent NaH6 octahedra. The corner-sharing octahedra tilt angles range from 33–71°. All Al–H bond lengths are 1.75 Å. In the second Al3+ site, Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with two equivalent AlH6 octahedra and corners with eight equivalent NaH6 octahedra. The corner-sharing octahedra tilt angles range from 33–68°. There is four shorter (1.74 Å) and two longer (1.78 Å) Al–H bond length. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted single-bond geometry to four equivalent Na1+ and one Al3+ atom. In the second H1- site, H1- is bonded in a bent 150 degrees geometry to two Al3+ atoms. In the third H1- site, H1- is bonded to three Na1+ and one Al3+ atom to form a mixture of distorted corner and edge-sharing HNa3Al trigonal pyramids.
LiAlMg10H24 is Hydrophilite-derived structured and crystallizes in the monoclinic P2 space group. The structure is three-dimensional. Li1+ is bonded to six H1- atoms to form LiH6 octahedra that share corners with eight MgH6 octahedra, an edgeedge with one MgH6 octahedra, and an edgeedge with one AlH6 octahedra. The corner-sharing octahedra tilt angles range from 47–64°. There are a spread of Li–H bond distances ranging from 1.91–2.15 Å. There are seven inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six H1- atoms to form a mixture of corner and edge-sharing MgH6 octahedra. The corner-sharing octahedra tilt angles range from 48–52°. There is two shorter (1.92 Å) and four longer (1.97 Å) Mg–H bond length. In the second Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with two equivalent LiH6 octahedra, corners with two equivalent AlH6 octahedra, corners with four MgH6 octahedra, and edges with two MgH6 octahedra. The corner-sharing octahedra tilt angles range from 38–64°. There are a spread of Mg–H bond distances ranging from 1.88–2.04 Å. In the third Mg2+ site, Mg2+ is bonded to six H1- atoms to form a mixture of corner and edge-sharing MgH6 octahedra. The corner-sharing octahedra tilt angles range from 48–52°. There are a spread of Mg–H bond distances ranging from 1.92–1.97 Å. In the fourth Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with eight MgH6 octahedra, an edgeedge with one LiH6 octahedra, and an edgeedge with one AlH6 octahedra. The corner-sharing octahedra tilt angles range from 45–60°. There are a spread of Mg–H bond distances ranging from 1.88–2.07 Å. In the fifth Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with two equivalent LiH6 octahedra, corners with six MgH6 octahedra, and edges with two MgH6 octahedra. The corner-sharing octahedra tilt angles range from 46–57°. There are a spread of Mg–H bond distances ranging from 1.88–2.00 Å. In the sixth Mg2+ site, Mg2+ is bonded to six H1- atoms to form a mixture of corner and edge-sharing MgH6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are a spread of Mg–H bond distances ranging from 1.94–1.96 Å. In the seventh Mg2+ site, Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with two equivalent AlH6 octahedra, corners with six MgH6 octahedra, and edges with two MgH6 octahedra. The corner-sharing octahedra tilt angles range from 44–60°. There are a spread of Mg–H bond distances ranging from 1.90–2.03 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with eight MgH6 octahedra, an edgeedge with one LiH6 octahedra, and an edgeedge with one MgH6 octahedra. The corner-sharing octahedra tilt angles range from 38–51°. There are a spread of Al–H bond distances ranging from 1.71–1.79 Å. There are twelve inequivalent H1- sites. In the first H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the second H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the third H1- site, H1- is bonded in a trigonal planar geometry to one Li1+ and two Mg2+ atoms. In the fourth H1- site, H1- is bonded in a distorted trigonal planar geometry to one Li1+ and two Mg2+ atoms. In the fifth H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the sixth H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the seventh H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the eighth H1- site, H1- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Al3+ atom. In the ninth H1- site, H1- is bonded in a distorted trigonal planar geometry to one Li1+, one Mg2+, and one Al3+ atom. In the tenth H1- site, H1- is bonded in a distorted trigonal planar geometry to three Mg2+ atoms. In the eleventh H1- site, H1- is bonded in a trigonal planar geometry to three Mg2+ atoms. In the twelfth H1- site, H1- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Al3+ atom.
SrAlH5 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Sr2+ is bonded to twelve H1- atoms to form distorted SrH12 cuboctahedra that share corners with four equivalent SrH12 cuboctahedra, corners with two equivalent AlH6 octahedra, edges with four equivalent SrH12 cuboctahedra, an edgeedge with one AlH6 octahedra, faces with two equivalent SrH12 cuboctahedra, and faces with three equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 46–49°. There are a spread of Sr–H bond distances ranging from 2.47–2.83 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with two equivalent SrH12 cuboctahedra, corners with two equivalent AlH6 octahedra, an edgeedge with one SrH12 cuboctahedra, and faces with three equivalent SrH12 cuboctahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of Al–H bond distances ranging from 1.70–1.82 Å. There are five inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a 1-coordinate geometry to three equivalent Sr2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a distorted single-bond geometry to three equivalent Sr2+ and one Al3+ atom. In the fourth H1- site, H1- is bonded in a distorted single-bond geometry to three equivalent Sr2+ and one Al3+ atom. In the fifth H1- site, H1- is bonded in a 2-coordinate geometry to one Sr2+ and two equivalent Al3+ atoms.
CaAlH5 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Ca2+ is bonded to twelve H1- atoms to form distorted CaH12 cuboctahedra that share corners with four equivalent CaH12 cuboctahedra, corners with two equivalent AlH6 octahedra, edges with four equivalent CaH12 cuboctahedra, an edgeedge with one AlH6 octahedra, faces with two equivalent CaH12 cuboctahedra, and faces with three equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 48–51°. There are a spread of Ca–H bond distances ranging from 2.34–2.66 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with two equivalent CaH12 cuboctahedra, corners with two equivalent AlH6 octahedra, an edgeedge with one CaH12 cuboctahedra, and faces with three equivalent CaH12 cuboctahedra. The corner-sharing octahedral tilt angles are 47°. There are a spread of Al–H bond distances ranging from 1.69–1.79 Å. There are five inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted single-bond geometry to two equivalent Ca2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a 1-coordinate geometry to three equivalent Ca2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one Al3+ atom. In the fourth H1- site, H1- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one Al3+ atom. In the fifth H1- site, H1- is bonded in a 3-coordinate geometry to one Ca2+ and two equivalent Al3+ atoms.
Li3AlH6 is Ilmenite-like structured and crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Li1+ is bonded to six H1- atoms to form distorted LiH6 pentagonal pyramids that share corners with two AlH6 octahedra, corners with four equivalent LiH6 pentagonal pyramids, edges with two AlH6 octahedra, and edges with four equivalent LiH6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 34–41°. There are a spread of Li–H bond distances ranging from 1.90–2.08 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 pentagonal pyramids and edges with six equivalent LiH6 pentagonal pyramids. All Al–H bond lengths are 1.75 Å. In the second Al3+ site, Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 pentagonal pyramids and edges with six equivalent LiH6 pentagonal pyramids. All Al–H bond lengths are 1.75 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted see-saw-like geometry to three equivalent Li1+ and one Al3+ atom. In the second H1- site, H1- is bonded to three equivalent Li1+ and one Al3+ atom to form a mixture of edge and corner-sharing HLi3Al trigonal pyramids.
Al(BH4)3 is Protactinium-like structured and crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of four Al(BH4)3 clusters. Al3+ is bonded to six H+0.50+ atoms to form distorted AlH6 pentagonal pyramids that share edges with three BH4 tetrahedra. There is two shorter (1.77 Å) and four longer (1.78 Å) Al–H bond length. There are three inequivalent B3- sites. In the first B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share an edgeedge with one AlH6 pentagonal pyramid. There is two shorter (1.20 Å) and two longer (1.27 Å) B–H bond length. In the second B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share an edgeedge with one AlH6 pentagonal pyramid. There is two shorter (1.20 Å) and two longer (1.27 Å) B–H bond length. In the third B3- site, B3- is bonded to four H+0.50+ atoms to form BH4 tetrahedra that share an edgeedge with one AlH6 pentagonal pyramid. There is two shorter (1.20 Å) and two longer (1.27 Å) B–H bond length. There are twelve inequivalent H+0.50+ sites. In the first H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Al3+ and one B3- atom. In the second H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Al3+ and one B3- atom. In the third H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom. In the fourth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Al3+ and one B3- atom. In the fifth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Al3+ and one B3- atom. In the sixth H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom. In the seventh H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Al3+ and one B3- atom. In the eighth H+0.50+ site, H+0.50+ is bonded in an L-shaped geometry to one Al3+ and one B3- atom. In the ninth H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom. In the tenth H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom. In the eleventh H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom. In the twelfth H+0.50+ site, H+0.50+ is bonded in a single-bond geometry to one B3- atom.
MgAlH5 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. Mg2+ is bonded to six H1- atoms to form MgH6 octahedra that share corners with four equivalent MgH6 octahedra, corners with four equivalent AlH6 octahedra, and an edgeedge with one AlH6 octahedra. The corner-sharing octahedra tilt angles range from 41–57°. There are a spread of Mg–H bond distances ranging from 1.86–2.02 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with two equivalent AlH6 octahedra, corners with four equivalent MgH6 octahedra, and an edgeedge with one MgH6 octahedra. The corner-sharing octahedra tilt angles range from 41–57°. There are a spread of Al–H bond distances ranging from 1.68–1.79 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a bent 150 degrees geometry to one Mg2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a trigonal planar geometry to two equivalent Mg2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a bent 120 degrees geometry to two equivalent Al3+ atoms.
K2LiAlH6 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. K1+ is bonded to twelve equivalent H1- atoms to form KH12 cuboctahedra that share corners with twelve equivalent KH12 cuboctahedra, faces with six equivalent KH12 cuboctahedra, faces with four equivalent LiH6 octahedra, and faces with four equivalent AlH6 octahedra. All K–H bond lengths are 2.77 Å. Li1+ is bonded to six equivalent H1- atoms to form LiH6 octahedra that share corners with six equivalent AlH6 octahedra and faces with eight equivalent KH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Li–H bond lengths are 2.12 Å. Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 octahedra and faces with eight equivalent KH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–H bond lengths are 1.79 Å. H1- is bonded in a distorted linear geometry to four equivalent K1+, one Li1+, and one Al3+ atom.
K2NaAlH6 is (Cubic) Perovskite-derived structured and crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. K1+ is bonded to twelve H1- atoms to form KH12 cuboctahedra that share corners with twelve equivalent KH12 cuboctahedra, faces with six equivalent KH12 cuboctahedra, faces with four equivalent NaH6 octahedra, and faces with four equivalent AlH6 octahedra. There are a spread of K–H bond distances ranging from 2.86–2.91 Å. Na1+ is bonded to six H1- atoms to form NaH6 octahedra that share corners with six equivalent AlH6 octahedra and faces with eight equivalent KH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.28 Å) and four longer (2.29 Å) Na–H bond lengths. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with six equivalent NaH6 octahedra and faces with eight equivalent KH12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–2°. All Al–H bond lengths are 1.78 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded in a distorted linear geometry to four equivalent K1+, one Na1+, and one Al3+ atom. In the second H1- site, H1- is bonded in a distorted linear geometry to four equivalent K1+, one Na1+, and one Al3+ atom.
BeAlH5 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Be2+ is bonded to four H1- atoms to form BeH4 tetrahedra that share corners with two equivalent AlH6 octahedra and corners with two equivalent BeH4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Be–H bond distances ranging from 1.43–1.45 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with four equivalent AlH6 octahedra and corners with two equivalent BeH4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–43°. There are a spread of Al–H bond distances ranging from 1.70–1.74 Å. There are five inequivalent H1- sites. In the first H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Be2+ atoms. In the second H1- site, H1- is bonded in a bent 120 degrees geometry to one Be2+ and one Al3+ atom. In the third H1- site, H1- is bonded in a bent 120 degrees geometry to one Be2+ and one Al3+ atom. In the fourth H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms. In the fifth H1- site, H1- is bonded in a bent 150 degrees geometry to two equivalent Al3+ atoms.
BeAlH5 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Be2+ is bonded to four H1- atoms to form BeH4 tetrahedra that share corners with four equivalent AlH6 octahedra. The corner-sharing octahedra tilt angles range from 41–52°. All Be–H bond lengths are 1.43 Å. Al3+ is bonded to six H1- atoms to form AlH6 octahedra that share corners with two equivalent AlH6 octahedra and corners with four equivalent BeH4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Al–H bond distances ranging from 1.71–1.73 Å. There are three inequivalent H1- sites. In the first H1- site, H1- is bonded in a bent 150 degrees geometry to one Be2+ and one Al3+ atom. In the second H1- site, H1- is bonded in a distorted bent 150 degrees geometry to two equivalent Al3+ atoms. In the third H1- site, H1- is bonded in a bent 120 degrees geometry to one Be2+ and one Al3+ atom.
Na2LiAlH6 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Na1+ is bonded to twelve equivalent H1- atoms to form NaH12 cuboctahedra that share corners with twelve equivalent NaH12 cuboctahedra, faces with six equivalent NaH12 cuboctahedra, faces with four equivalent LiH6 octahedra, and faces with four equivalent AlH6 octahedra. All Na–H bond lengths are 2.60 Å. Li1+ is bonded to six equivalent H1- atoms to form LiH6 octahedra that share corners with six equivalent AlH6 octahedra and faces with eight equivalent NaH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Li–H bond lengths are 1.92 Å. Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent LiH6 octahedra and faces with eight equivalent NaH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–H bond lengths are 1.75 Å. H1- is bonded in a distorted linear geometry to four equivalent Na1+, one Li1+, and one Al3+ atom.
Cs2NaAlH6 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cs1+ is bonded to twelve equivalent H1- atoms to form CsH12 cuboctahedra that share corners with twelve equivalent CsH12 cuboctahedra, faces with six equivalent CsH12 cuboctahedra, faces with four equivalent NaH6 octahedra, and faces with four equivalent AlH6 octahedra. All Cs–H bond lengths are 3.07 Å. Na1+ is bonded to six equivalent H1- atoms to form NaH6 octahedra that share corners with six equivalent AlH6 octahedra and faces with eight equivalent CsH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Na–H bond lengths are 2.51 Å. Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent NaH6 octahedra and faces with eight equivalent CsH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–H bond lengths are 1.80 Å. H1- is bonded in a 2-coordinate geometry to four equivalent Cs1+, one Na1+, and one Al3+ atom.
PrAlH6 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pr3+ is bonded to twelve equivalent H1- atoms to form PrH12 cuboctahedra that share corners with six equivalent AlH6 octahedra, edges with six equivalent PrH12 cuboctahedra, and faces with two equivalent AlH6 octahedra. The corner-sharing octahedral tilt angles are 41°. There are six shorter (2.41 Å) and six longer (2.42 Å) Pr–H bond lengths. Al3+ is bonded to six equivalent H1- atoms to form AlH6 octahedra that share corners with six equivalent PrH12 cuboctahedra and faces with two equivalent PrH12 cuboctahedra. All Al–H bond lengths are 1.73 Å. H1- is bonded in a distorted single-bond geometry to two equivalent Pr3+ and one Al3+ atom.
KAlH3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. K is bonded to twelve equivalent H atoms to form KH12 cuboctahedra that share corners with twelve equivalent KH12 cuboctahedra, faces with six equivalent KH12 cuboctahedra, and faces with eight equivalent AlH6 octahedra. All K–H bond lengths are 2.82 Å. Al is bonded to six equivalent H atoms to form AlH6 octahedra that share corners with six equivalent AlH6 octahedra and faces with eight equivalent KH12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Al–H bond lengths are 1.99 Å. H is bonded to four equivalent K and two equivalent Al atoms to form a mixture of distorted edge, corner, and face-sharing HK4Al2 octahedra. The corner-sharing octahedra tilt angles range from 0–60°.