Sr2TmCu2(BiO4)2 crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent O(3) atoms. Tm(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted CuO5 square pyramids that share  a cornercorner with one Bi(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. Bi(1) is bonded to one O(3) and five equivalent O(2) atoms to form distorted BiO6 octahedra that share corners with four equivalent Bi(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and edges with eight equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Tm(1), and two equivalent Cu(1) atoms to form distorted OSr2Tm2Cu2 octahedra that share corners with two equivalent O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Tm2Cu2 octahedra, edges with three equivalent O(1)Sr2Tm2Cu2 octahedra, faces with two equivalent O(3)Sr4CuBi octahedra, and faces with four equivalent O(1)Sr2Tm2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded to one Sr(1) and five equivalent Bi(1) atoms to form OSrBi5 octahedra that share  a cornercorner with one O(3)Sr4CuBi octahedra, corners with four equivalent O(1)Sr2Tm2Cu2 octahedra, corners with four equivalent O(2)SrBi5 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, and edges with eight equivalent O(2)SrBi5 octahedra. The corner-sharing octahedral tilt angles range from 0-42°. In the third O site, O(3) is bonded to four equivalent Sr(1), one Cu(1), and one Bi(1) atom to form distorted OSr4CuBi octahedra that share  a cornercorner with one O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Tm2Cu2 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, edges with four equivalent O(2)SrBi5 octahedra, and faces with four equivalent O(1)Sr2Tm2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-51°.
Sr2TmCu2(BiO4)2 crystallizes in the tetragonal I4/mmm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(2), four equivalent O(1), and four equivalent O(3) atoms. The Sr(1)-O(2) bond length is 2.67 Å. All Sr(1)-O(1) bond lengths are 2.79 Å. All Sr(1)-O(3) bond lengths are 2.73 Å. Tm(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Tm(1)-O(1) bond lengths are 2.37 Å. Cu(1) is bonded to one O(3) and four equivalent O(1) atoms to form distorted CuO5 square pyramids that share  a cornercorner with one Bi(1)O6 octahedra and corners with four equivalent Cu(1)O5 square pyramids. The corner-sharing octahedra are not tilted. The Cu(1)-O(3) bond length is 2.50 Å. All Cu(1)-O(1) bond lengths are 1.89 Å. Bi(1) is bonded to one O(3) and five equivalent O(2) atoms to form distorted BiO6 octahedra that share corners with four equivalent Bi(1)O6 octahedra,  a cornercorner with one Cu(1)O5 square pyramid, and edges with eight equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles are 3°. The Bi(1)-O(3) bond length is 2.14 Å. There are four shorter (2.66 Å) and one longer (2.78 Å) Bi(1)-O(2) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Tm(1), and two equivalent Cu(1) atoms to form distorted OSr2Tm2Cu2 octahedra that share corners with two equivalent O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Tm2Cu2 octahedra, edges with three equivalent O(1)Sr2Tm2Cu2 octahedra, faces with two equivalent O(3)Sr4CuBi octahedra, and faces with four equivalent O(1)Sr2Tm2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-68°. In the second O site, O(2) is bonded to one Sr(1) and five equivalent Bi(1) atoms to form OSrBi5 octahedra that share  a cornercorner with one O(3)Sr4CuBi octahedra, corners with four equivalent O(1)Sr2Tm2Cu2 octahedra, corners with four equivalent O(2)SrBi5 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, and edges with eight equivalent O(2)SrBi5 octahedra. The corner-sharing octahedral tilt angles range from 0-42°. In the third O site, O(3) is bonded to four equivalent Sr(1), one Cu(1), and one Bi(1) atom to form distorted OSr4CuBi octahedra that share  a cornercorner with one O(2)SrBi5 octahedra, corners with four equivalent O(3)Sr4CuBi octahedra, corners with eight equivalent O(1)Sr2Tm2Cu2 octahedra, edges with four equivalent O(3)Sr4CuBi octahedra, edges with four equivalent O(2)SrBi5 octahedra, and faces with four equivalent O(1)Sr2Tm2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-51°.