LaCo5H4 crystallizes in the orthorhombic Cmmm space group. La(1) is bonded in a 8-coordinate geometry to four equivalent H(1) and four equivalent H(2) atoms. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a water-like geometry to two equivalent Co(3) and two equivalent H(2) atoms. In the second Co site, Co(2) is bonded in a distorted square co-planar geometry to two equivalent Co(3), two equivalent H(1), and two equivalent H(2) atoms. In the third Co site, Co(3) is bonded in a 8-coordinate geometry to four equivalent Co(1) and four equivalent Co(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to two equivalent La(1) and two equivalent Co(2) atoms to form HLa2Co2 tetrahedra that share corners with four equivalent H(2)La2Co4 octahedra, corners with six equivalent H(1)La2Co2 tetrahedra, edges with four equivalent H(2)La2Co4 octahedra, and  an edgeedge with one H(1)La2Co2 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the second H site, H(2) is bonded to two equivalent La(1), two equivalent Co(1), and two equivalent Co(2) atoms to form distorted HLa2Co4 octahedra that share corners with six equivalent H(2)La2Co4 octahedra, corners with four equivalent H(1)La2Co2 tetrahedra, edges with two equivalent H(2)La2Co4 octahedra, and edges with four equivalent H(1)La2Co2 tetrahedra. The corner-sharing octahedral tilt angles range from 0-63°.
LaCo5H4 crystallizes in the orthorhombic Cmmm space group. La(1) is bonded in a 8-coordinate geometry to four equivalent H(1) and four equivalent H(2) atoms. All La(1)-H(1) bond lengths are 2.41 Å. All La(1)-H(2) bond lengths are 2.61 Å. There are three inequivalent Co sites. In the first Co site, Co(1) is bonded in a water-like geometry to two equivalent Co(3) and two equivalent H(2) atoms. Both Co(1)-Co(3) bond lengths are 2.35 Å. Both Co(1)-H(2) bond lengths are 1.71 Å. In the second Co site, Co(2) is bonded in a distorted square co-planar geometry to two equivalent Co(3), two equivalent H(1), and two equivalent H(2) atoms. Both Co(2)-Co(3) bond lengths are 2.61 Å. Both Co(2)-H(1) bond lengths are 1.64 Å. Both Co(2)-H(2) bond lengths are 2.02 Å. In the third Co site, Co(3) is bonded in a 8-coordinate geometry to four equivalent Co(1) and four equivalent Co(2) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded to two equivalent La(1) and two equivalent Co(2) atoms to form HLa2Co2 tetrahedra that share corners with four equivalent H(2)La2Co4 octahedra, corners with six equivalent H(1)La2Co2 tetrahedra, edges with four equivalent H(2)La2Co4 octahedra, and  an edgeedge with one H(1)La2Co2 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the second H site, H(2) is bonded to two equivalent La(1), two equivalent Co(1), and two equivalent Co(2) atoms to form distorted HLa2Co4 octahedra that share corners with six equivalent H(2)La2Co4 octahedra, corners with four equivalent H(1)La2Co2 tetrahedra, edges with two equivalent H(2)La2Co4 octahedra, and edges with four equivalent H(1)La2Co2 tetrahedra. The corner-sharing octahedral tilt angles range from 0-63°.