DOE OSTI2020
Ba2H3I crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ba2+ is bonded in a 4-coordinate geometry to seven H1- and three equivalent I1- atoms. There are a spread of Ba–H bond distances ranging from 2.64–3.02 Å. All Ba–I bond lengths are 3.67 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent Ba2+ atoms to form HBa4 trigonal pyramids that share corners with three equivalent HBa6 octahedra, corners with six equivalent IBa6 octahedra, corners with six equivalent HBa4 trigonal pyramids, edges with three equivalent IBa6 octahedra, edges with three equivalent HBa4 trigonal pyramids, and faces with three equivalent HBa6 octahedra. The corner-sharing octahedra tilt angles range from 37–45°. In the second H1- site, H1- is bonded to six equivalent Ba2+ atoms to form HBa6 octahedra that share corners with twelve equivalent IBa6 octahedra, corners with six equivalent HBa4 trigonal pyramids, edges with six equivalent HBa6 octahedra, faces with two equivalent IBa6 octahedra, and faces with six equivalent HBa4 trigonal pyramids. The corner-sharing octahedral tilt angles are 49°. I1- is bonded to six equivalent Ba2+ atoms to form distorted IBa6 octahedra that share corners with twelve equivalent HBa6 octahedra, corners with twelve equivalent HBa4 trigonal pyramids, edges with six equivalent IBa6 octahedra, edges with six equivalent HBa4 trigonal pyramids, and faces with two equivalent HBa6 octahedra. The corner-sharing octahedral tilt angles are 49°.