K3Cu2F7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to four equivalent F(1) and five equivalent F(3) atoms. In the second K site, K(2) is bonded to four equivalent F(2) and eight equivalent F(1) atoms to form KF12 cuboctahedra that share corners with four equivalent K(2)F12 cuboctahedra, faces with four equivalent K(2)F12 cuboctahedra, and faces with eight equivalent Cu(1)F6 octahedra. Cu(1) is bonded to one F(2), one F(3), and four equivalent F(1) atoms to form CuF6 octahedra that share corners with five equivalent Cu(1)F6 octahedra and faces with four equivalent K(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. There are three inequivalent F sites. In the first F site, F(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent Cu(1) atoms to form distorted FK4Cu2 octahedra that share corners with four equivalent F(2)K4Cu2 octahedra, corners with six equivalent F(3)K5Cu octahedra, corners with eight equivalent F(1)K4Cu2 octahedra, edges with three equivalent F(1)K4Cu2 octahedra, faces with two equivalent F(2)K4Cu2 octahedra, faces with two equivalent F(3)K5Cu octahedra, and faces with four equivalent F(1)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the second F site, F(2) is bonded to four equivalent K(2) and two equivalent Cu(1) atoms to form distorted FK4Cu2 octahedra that share corners with two equivalent F(3)K5Cu octahedra, corners with four equivalent F(2)K4Cu2 octahedra, corners with sixteen equivalent F(1)K4Cu2 octahedra, edges with four equivalent F(2)K4Cu2 octahedra, and faces with eight equivalent F(1)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the third F site, F(3) is bonded to five equivalent K(1) and one Cu(1) atom to form distorted FK5Cu octahedra that share  a cornercorner with one F(2)K4Cu2 octahedra, corners with four equivalent F(3)K5Cu octahedra, corners with twelve equivalent F(1)K4Cu2 octahedra, edges with eight equivalent F(3)K5Cu octahedra, and faces with four equivalent F(1)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°.
K3Cu2F7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to four equivalent F(1) and five equivalent F(3) atoms. All K(1)-F(1) bond lengths are 2.75 Å. There is one shorter (2.61 Å) and four longer (2.84 Å) K(1)-F(3) bond lengths. In the second K site, K(2) is bonded to four equivalent F(2) and eight equivalent F(1) atoms to form KF12 cuboctahedra that share corners with four equivalent K(2)F12 cuboctahedra, faces with four equivalent K(2)F12 cuboctahedra, and faces with eight equivalent Cu(1)F6 octahedra. All K(2)-F(2) bond lengths are 2.83 Å. All K(2)-F(1) bond lengths are 2.82 Å. Cu(1) is bonded to one F(2), one F(3), and four equivalent F(1) atoms to form CuF6 octahedra that share corners with five equivalent Cu(1)F6 octahedra and faces with four equivalent K(2)F12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Cu(1)-F(2) bond length is 2.01 Å. The Cu(1)-F(3) bond length is 2.00 Å. All Cu(1)-F(1) bond lengths are 2.00 Å. There are three inequivalent F sites. In the first F site, F(1) is bonded to two equivalent K(1), two equivalent K(2), and two equivalent Cu(1) atoms to form distorted FK4Cu2 octahedra that share corners with four equivalent F(2)K4Cu2 octahedra, corners with six equivalent F(3)K5Cu octahedra, corners with eight equivalent F(1)K4Cu2 octahedra, edges with three equivalent F(1)K4Cu2 octahedra, faces with two equivalent F(2)K4Cu2 octahedra, faces with two equivalent F(3)K5Cu octahedra, and faces with four equivalent F(1)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the second F site, F(2) is bonded to four equivalent K(2) and two equivalent Cu(1) atoms to form distorted FK4Cu2 octahedra that share corners with two equivalent F(3)K5Cu octahedra, corners with four equivalent F(2)K4Cu2 octahedra, corners with sixteen equivalent F(1)K4Cu2 octahedra, edges with four equivalent F(2)K4Cu2 octahedra, and faces with eight equivalent F(1)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the third F site, F(3) is bonded to five equivalent K(1) and one Cu(1) atom to form distorted FK5Cu octahedra that share  a cornercorner with one F(2)K4Cu2 octahedra, corners with four equivalent F(3)K5Cu octahedra, corners with twelve equivalent F(1)K4Cu2 octahedra, edges with eight equivalent F(3)K5Cu octahedra, and faces with four equivalent F(1)K4Cu2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°.