BaH2 crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded in a 11-coordinate geometry to five equivalent H(1) and six equivalent H(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to five equivalent Ba(1) atoms to form HBa5 trigonal bipyramids that share corners with twelve equivalent H(2)Ba6 octahedra, corners with eight equivalent H(1)Ba5 trigonal bipyramids, edges with six equivalent H(1)Ba5 trigonal bipyramids, and faces with six equivalent H(2)Ba6 octahedra. The corner-sharing octahedral tilt angles range from 30-60°. In the second H site, H(2) is bonded to six equivalent Ba(1) atoms to form HBa6 octahedra that share corners with twelve equivalent H(2)Ba6 octahedra, corners with twelve equivalent H(1)Ba5 trigonal bipyramids, edges with six equivalent H(2)Ba6 octahedra, faces with two equivalent H(2)Ba6 octahedra, and faces with six equivalent H(1)Ba5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°.
BaH2 crystallizes in the hexagonal P6_3/mmc space group. Ba(1) is bonded in a 11-coordinate geometry to five equivalent H(1) and six equivalent H(2) atoms. There are three shorter (2.58 Å) and two longer (3.03 Å) Ba(1)-H(1) bond lengths. All Ba(1)-H(2) bond lengths are 2.99 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded to five equivalent Ba(1) atoms to form HBa5 trigonal bipyramids that share corners with twelve equivalent H(2)Ba6 octahedra, corners with eight equivalent H(1)Ba5 trigonal bipyramids, edges with six equivalent H(1)Ba5 trigonal bipyramids, and faces with six equivalent H(2)Ba6 octahedra. The corner-sharing octahedral tilt angles range from 30-60°. In the second H site, H(2) is bonded to six equivalent Ba(1) atoms to form HBa6 octahedra that share corners with twelve equivalent H(2)Ba6 octahedra, corners with twelve equivalent H(1)Ba5 trigonal bipyramids, edges with six equivalent H(2)Ba6 octahedra, faces with two equivalent H(2)Ba6 octahedra, and faces with six equivalent H(1)Ba5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°.