K3MgHoV2O8 crystallizes in the monoclinic C2/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 3-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(3) atoms. In the second K site, K(2) is bonded in a linear geometry to two equivalent O(3) atoms. Mg(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. Ho(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form HoO6 octahedra that share corners with six equivalent V(1)O4 tetrahedra. V(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-21°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(1) and one V(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one Mg(1), one Ho(1), and one V(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Ho(1), and one V(1) atom.
K3MgHoV2O8 crystallizes in the monoclinic C2/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 3-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(3) atoms. The K(1)-O(1) bond length is 2.50 Å. Both K(1)-O(2) bond lengths are 2.81 Å. Both K(1)-O(3) bond lengths are 3.16 Å. In the second K site, K(2) is bonded in a linear geometry to two equivalent O(3) atoms. Both K(2)-O(3) bond lengths are 2.98 Å. Mg(1) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Mg(1)-O(2) bond lengths are 1.99 Å. Ho(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form HoO6 octahedra that share corners with six equivalent V(1)O4 tetrahedra. Both Ho(1)-O(3) bond lengths are 2.32 Å. All Ho(1)-O(2) bond lengths are 2.25 Å. V(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form VO4 tetrahedra that share corners with three equivalent Ho(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-21°. The V(1)-O(1) bond length is 1.71 Å. The V(1)-O(3) bond length is 1.80 Å. Both V(1)-O(2) bond lengths are 1.93 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one K(1) and one V(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one Mg(1), one Ho(1), and one V(1) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one K(2), two equivalent K(1), one Ho(1), and one V(1) atom.