K3ErF6 crystallizes in the cubic Fm-3m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to twelve equivalent F(1) atoms to form distorted KF12 cuboctahedra that share corners with twelve equivalent K(1)F12 cuboctahedra, faces with six equivalent K(1)F12 cuboctahedra, faces with four equivalent K(2)F6 octahedra, and faces with four equivalent Er(1)F6 octahedra. In the second K site, K(2) is bonded to six equivalent F(1) atoms to form KF6 octahedra that share corners with six equivalent Er(1)F6 octahedra and faces with eight equivalent K(1)F12 cuboctahedra. The corner-sharing octahedra are not tilted. Er(1) is bonded to six equivalent F(1) atoms to form ErF6 octahedra that share corners with six equivalent K(2)F6 octahedra and faces with eight equivalent K(1)F12 cuboctahedra. The corner-sharing octahedra are not tilted. F(1) is bonded in a linear geometry to one K(2), four equivalent K(1), and one Er(1) atom.
K3ErF6 crystallizes in the cubic Fm-3m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to twelve equivalent F(1) atoms to form distorted KF12 cuboctahedra that share corners with twelve equivalent K(1)F12 cuboctahedra, faces with six equivalent K(1)F12 cuboctahedra, faces with four equivalent K(2)F6 octahedra, and faces with four equivalent Er(1)F6 octahedra. All K(1)-F(1) bond lengths are 3.33 Å. In the second K site, K(2) is bonded to six equivalent F(1) atoms to form KF6 octahedra that share corners with six equivalent Er(1)F6 octahedra and faces with eight equivalent K(1)F12 cuboctahedra. The corner-sharing octahedra are not tilted. All K(2)-F(1) bond lengths are 2.54 Å. Er(1) is bonded to six equivalent F(1) atoms to form ErF6 octahedra that share corners with six equivalent K(2)F6 octahedra and faces with eight equivalent K(1)F12 cuboctahedra. The corner-sharing octahedra are not tilted. All Er(1)-F(1) bond lengths are 2.16 Å. F(1) is bonded in a linear geometry to one K(2), four equivalent K(1), and one Er(1) atom.