Sr3Cu2(OF)4 crystallizes in the tetragonal I-4m2 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent F(1) atoms to form SrO8F4 cuboctahedra that share corners with four equivalent Sr(1)O8F4 cuboctahedra, faces with four equivalent Sr(1)O8F4 cuboctahedra, and faces with eight equivalent Cu(1)O4F2 octahedra. In the second Sr site, Sr(2) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), two equivalent F(3), and four equivalent F(2) atoms. Cu(1) is bonded to two equivalent O(1), two equivalent O(2), one F(1), and one F(2) atom to form CuO4F2 octahedra that share corners with five equivalent Cu(1)O4F2 octahedra and faces with four equivalent Sr(1)O8F4 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-6°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms. There are three inequivalent F sites. In the first F site, F(1) is bonded to four equivalent Sr(1) and two equivalent Cu(1) atoms to form FSr4Cu2 octahedra that share corners with four equivalent F(1)Sr4Cu2 octahedra, corners with two equivalent F(2)Sr4Cu square pyramids, and edges with four equivalent F(1)Sr4Cu2 octahedra. The corner-sharing octahedra are not tilted. In the second F site, F(2) is bonded to four equivalent Sr(2) and one Cu(1) atom to form FSr4Cu square pyramids that share  a cornercorner with one F(1)Sr4Cu2 octahedra, corners with four equivalent F(2)Sr4Cu square pyramids, corners with four equivalent F(3)Sr4 tetrahedra, edges with four equivalent F(2)Sr4Cu square pyramids, and edges with two equivalent F(3)Sr4 tetrahedra. The corner-sharing octahedra are not tilted. In the third F site, F(3) is bonded to four equivalent Sr(2) atoms to form distorted FSr4 tetrahedra that share corners with eight equivalent F(2)Sr4Cu square pyramids, corners with four equivalent F(3)Sr4 tetrahedra, and edges with four equivalent F(2)Sr4Cu square pyramids.
Sr3Cu2(OF)4 crystallizes in the tetragonal I-4m2 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent F(1) atoms to form SrO8F4 cuboctahedra that share corners with four equivalent Sr(1)O8F4 cuboctahedra, faces with four equivalent Sr(1)O8F4 cuboctahedra, and faces with eight equivalent Cu(1)O4F2 octahedra. All Sr(1)-O(1) bond lengths are 2.87 Å. All Sr(1)-O(2) bond lengths are 2.76 Å. All Sr(1)-F(1) bond lengths are 2.69 Å. In the second Sr site, Sr(2) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), two equivalent F(3), and four equivalent F(2) atoms. Both Sr(2)-O(1) bond lengths are 2.68 Å. Both Sr(2)-O(2) bond lengths are 2.78 Å. Both Sr(2)-F(3) bond lengths are 2.63 Å. All Sr(2)-F(2) bond lengths are 2.70 Å. Cu(1) is bonded to two equivalent O(1), two equivalent O(2), one F(1), and one F(2) atom to form CuO4F2 octahedra that share corners with five equivalent Cu(1)O4F2 octahedra and faces with four equivalent Sr(1)O8F4 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-6°. Both Cu(1)-O(1) bond lengths are 1.91 Å. Both Cu(1)-O(2) bond lengths are 1.91 Å. The Cu(1)-F(1) bond length is 2.10 Å. The Cu(1)-F(2) bond length is 2.07 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cu(1) atoms. There are three inequivalent F sites. In the first F site, F(1) is bonded to four equivalent Sr(1) and two equivalent Cu(1) atoms to form FSr4Cu2 octahedra that share corners with four equivalent F(1)Sr4Cu2 octahedra, corners with two equivalent F(2)Sr4Cu square pyramids, and edges with four equivalent F(1)Sr4Cu2 octahedra. The corner-sharing octahedra are not tilted. In the second F site, F(2) is bonded to four equivalent Sr(2) and one Cu(1) atom to form FSr4Cu square pyramids that share  a cornercorner with one F(1)Sr4Cu2 octahedra, corners with four equivalent F(2)Sr4Cu square pyramids, corners with four equivalent F(3)Sr4 tetrahedra, edges with four equivalent F(2)Sr4Cu square pyramids, and edges with two equivalent F(3)Sr4 tetrahedra. The corner-sharing octahedra are not tilted. In the third F site, F(3) is bonded to four equivalent Sr(2) atoms to form distorted FSr4 tetrahedra that share corners with eight equivalent F(2)Sr4Cu square pyramids, corners with four equivalent F(3)Sr4 tetrahedra, and edges with four equivalent F(2)Sr4Cu square pyramids.