Tm2CuO4 crystallizes in the orthorhombic Fmm2 space group. Tm(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. Cu(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Tm(1) atoms to form OTm4 tetrahedra that share corners with twelve equivalent O(2)Tm4Cu2 octahedra, corners with four equivalent O(1)Tm4 tetrahedra, edges with two equivalent O(2)Tm4Cu2 octahedra, and edges with four equivalent O(1)Tm4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-74°. In the second O site, O(2) is bonded to four equivalent Tm(1) and two equivalent Cu(1) atoms to form distorted OTm4Cu2 octahedra that share corners with two equivalent O(2)Tm4Cu2 octahedra, corners with twelve equivalent O(1)Tm4 tetrahedra, edges with two equivalent O(2)Tm4Cu2 octahedra, edges with two equivalent O(1)Tm4 tetrahedra, and faces with four equivalent O(2)Tm4Cu2 octahedra. The corner-sharing octahedral tilt angles are 4°.
Tm2CuO4 crystallizes in the orthorhombic Fmm2 space group. Tm(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two shorter (2.22 Å) and two longer (2.23 Å) Tm(1)-O(1) bond lengths. There are two shorter (2.49 Å) and two longer (2.74 Å) Tm(1)-O(2) bond lengths. Cu(1) is bonded in a rectangular see-saw-like geometry to four equivalent O(2) atoms. There are two shorter (1.91 Å) and two longer (1.93 Å) Cu(1)-O(2) bond lengths. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Tm(1) atoms to form OTm4 tetrahedra that share corners with twelve equivalent O(2)Tm4Cu2 octahedra, corners with four equivalent O(1)Tm4 tetrahedra, edges with two equivalent O(2)Tm4Cu2 octahedra, and edges with four equivalent O(1)Tm4 tetrahedra. The corner-sharing octahedral tilt angles range from 10-74°. In the second O site, O(2) is bonded to four equivalent Tm(1) and two equivalent Cu(1) atoms to form distorted OTm4Cu2 octahedra that share corners with two equivalent O(2)Tm4Cu2 octahedra, corners with twelve equivalent O(1)Tm4 tetrahedra, edges with two equivalent O(2)Tm4Cu2 octahedra, edges with two equivalent O(1)Tm4 tetrahedra, and faces with four equivalent O(2)Tm4Cu2 octahedra. The corner-sharing octahedral tilt angles are 4°.