Cs2TmH4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. Cs(1) is bonded in a 9-coordinate geometry to four equivalent H(2) and five equivalent H(1) atoms. Tm(1) is bonded to two equivalent H(1) and four equivalent H(2) atoms to form corner-sharing TmH6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent H sites. In the first H site, H(2) is bonded in a linear geometry to four equivalent Cs(1) and two equivalent Tm(1) atoms. In the second H site, H(1) is bonded in a distorted single-bond geometry to five equivalent Cs(1) and one Tm(1) atom.
Cs2TmH4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. Cs(1) is bonded in a 9-coordinate geometry to four equivalent H(2) and five equivalent H(1) atoms. All Cs(1)-H(2) bond lengths are 3.32 Å. There are four shorter (3.13 Å) and one longer (3.40 Å) Cs(1)-H(1) bond length. Tm(1) is bonded to two equivalent H(1) and four equivalent H(2) atoms to form corner-sharing TmH6 octahedra. The corner-sharing octahedra are not tilted. Both Tm(1)-H(1) bond lengths are 2.18 Å. All Tm(1)-H(2) bond lengths are 2.20 Å. There are two inequivalent H sites. In the first H site, H(2) is bonded in a linear geometry to four equivalent Cs(1) and two equivalent Tm(1) atoms. In the second H site, H(1) is bonded in a distorted single-bond geometry to five equivalent Cs(1) and one Tm(1) atom.