Ba3Ir2H12 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to twelve equivalent H(2) atoms to form BaH12 cuboctahedra that share edges with six equivalent Ba(1)H12 cuboctahedra, edges with six equivalent Ba(2)H12 cuboctahedra, and edges with six equivalent Ir(1)H6 octahedra. In the second Ba site, Ba(2) is bonded to three equivalent H(2) and nine equivalent H(1) atoms to form distorted BaH12 cuboctahedra that share corners with six equivalent Ba(2)H12 cuboctahedra, edges with three equivalent Ba(1)H12 cuboctahedra, faces with three equivalent Ba(2)H12 cuboctahedra, and faces with four equivalent Ir(1)H6 octahedra. Ir(1) is bonded to three equivalent H(1) and three equivalent H(2) atoms to form IrH6 octahedra that share edges with three equivalent Ba(1)H12 cuboctahedra and faces with four equivalent Ba(2)H12 cuboctahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a rectangular see-saw-like geometry to three equivalent Ba(2) and one Ir(1) atom. In the second H site, H(2) is bonded to one Ba(2), two equivalent Ba(1), and one Ir(1) atom to form a mixture of distorted corner and edge-sharing HBa3Ir tetrahedra.
Ba3Ir2H12 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to twelve equivalent H(2) atoms to form BaH12 cuboctahedra that share edges with six equivalent Ba(1)H12 cuboctahedra, edges with six equivalent Ba(2)H12 cuboctahedra, and edges with six equivalent Ir(1)H6 octahedra. All Ba(1)-H(2) bond lengths are 2.99 Å. In the second Ba site, Ba(2) is bonded to three equivalent H(2) and nine equivalent H(1) atoms to form distorted BaH12 cuboctahedra that share corners with six equivalent Ba(2)H12 cuboctahedra, edges with three equivalent Ba(1)H12 cuboctahedra, faces with three equivalent Ba(2)H12 cuboctahedra, and faces with four equivalent Ir(1)H6 octahedra. All Ba(2)-H(2) bond lengths are 2.77 Å. There are six shorter (2.76 Å) and three longer (2.97 Å) Ba(2)-H(1) bond lengths. Ir(1) is bonded to three equivalent H(1) and three equivalent H(2) atoms to form IrH6 octahedra that share edges with three equivalent Ba(1)H12 cuboctahedra and faces with four equivalent Ba(2)H12 cuboctahedra. All Ir(1)-H(1) bond lengths are 1.69 Å. All Ir(1)-H(2) bond lengths are 1.66 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a rectangular see-saw-like geometry to three equivalent Ba(2) and one Ir(1) atom. In the second H site, H(2) is bonded to one Ba(2), two equivalent Ba(1), and one Ir(1) atom to form a mixture of distorted corner and edge-sharing HBa3Ir tetrahedra.