Gd3Al2(Ni2H3)3 crystallizes in the cubic Im-3m space group. Gd(1) is bonded in a 5-coordinate geometry to one H(3), one H(4), and four equivalent H(1) atoms. Ni(1) is bonded in a 2-coordinate geometry to one H(3) and two equivalent H(2) atoms. Al(1) is bonded in a distorted linear geometry to two equivalent H(1) atoms. There are four inequivalent H sites. In the first H site, H(1) is bonded to three equivalent Gd(1) and one Al(1) atom to form HGd3Al tetrahedra that share corners with three equivalent H(3)Gd2Ni4 octahedra, corners with four equivalent H(1)Gd3Al tetrahedra, edges with three equivalent H(1)Gd3Al tetrahedra, and  a faceface with one H(4)Gd6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the second H site, H(2) is bonded to four equivalent Ni(1) atoms to form HNi4 tetrahedra that share corners with four equivalent H(2)Ni4 tetrahedra and edges with two equivalent H(3)Gd2Ni4 octahedra. In the third H site, H(3) is bonded to two equivalent Gd(1) and four equivalent Ni(1) atoms to form HGd2Ni4 octahedra that share corners with two equivalent H(4)Gd6 octahedra, corners with eight equivalent H(1)Gd3Al tetrahedra, and edges with four equivalent H(2)Ni4 tetrahedra. The corner-sharing octahedra are not tilted. In the fourth H site, H(4) is bonded to six equivalent Gd(1) atoms to form HGd6 octahedra that share corners with six equivalent H(3)Gd2Ni4 octahedra and faces with eight equivalent H(1)Gd3Al tetrahedra. The corner-sharing octahedra are not tilted.
Gd3Al2(Ni2H3)3 crystallizes in the cubic Im-3m space group. Gd(1) is bonded in a 5-coordinate geometry to one H(3), one H(4), and four equivalent H(1) atoms. The Gd(1)-H(3) bond length is 2.12 Å. The Gd(1)-H(4) bond length is 2.50 Å. All Gd(1)-H(1) bond lengths are 2.16 Å. Ni(1) is bonded in a 2-coordinate geometry to one H(3) and two equivalent H(2) atoms. The Ni(1)-H(3) bond length is 2.11 Å. Both Ni(1)-H(2) bond lengths are 1.70 Å. Al(1) is bonded in a distorted linear geometry to two equivalent H(1) atoms. Both Al(1)-H(1) bond lengths are 1.86 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded to three equivalent Gd(1) and one Al(1) atom to form HGd3Al tetrahedra that share corners with three equivalent H(3)Gd2Ni4 octahedra, corners with four equivalent H(1)Gd3Al tetrahedra, edges with three equivalent H(1)Gd3Al tetrahedra, and  a faceface with one H(4)Gd6 octahedra. The corner-sharing octahedral tilt angles are 54°. In the second H site, H(2) is bonded to four equivalent Ni(1) atoms to form HNi4 tetrahedra that share corners with four equivalent H(2)Ni4 tetrahedra and edges with two equivalent H(3)Gd2Ni4 octahedra. In the third H site, H(3) is bonded to two equivalent Gd(1) and four equivalent Ni(1) atoms to form HGd2Ni4 octahedra that share corners with two equivalent H(4)Gd6 octahedra, corners with eight equivalent H(1)Gd3Al tetrahedra, and edges with four equivalent H(2)Ni4 tetrahedra. The corner-sharing octahedra are not tilted. In the fourth H site, H(4) is bonded to six equivalent Gd(1) atoms to form HGd6 octahedra that share corners with six equivalent H(3)Gd2Ni4 octahedra and faces with eight equivalent H(1)Gd3Al tetrahedra. The corner-sharing octahedra are not tilted.