K4MgV2O7 crystallizes in the monoclinic Cm space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second K site, K(2) is bonded in a 2-coordinate geometry to one O(3), one O(5), and two equivalent O(1) atoms. In the third K site, K(3) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(4) atoms. In the fourth K site, K(4) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(4), and two equivalent O(5) atoms. Mg(1) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(2) atoms. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form corner-sharing VO4 tetrahedra. In the second V site, V(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form corner-sharing VO4 tetrahedra. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one K(1), one K(3), two equivalent K(2), and one V(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(3), one Mg(1), and one V(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(2), one K(4), two equivalent K(1), one Mg(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one K(3), one K(4), and one V(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one K(2), two equivalent K(4), one V(1), and one V(2) atom.
K4MgV2O7 crystallizes in the monoclinic Cm space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The K(1)-O(1) bond length is 2.72 Å. Both K(1)-O(2) bond lengths are 2.99 Å. Both K(1)-O(3) bond lengths are 3.07 Å. Both K(1)-O(4) bond lengths are 2.89 Å. In the second K site, K(2) is bonded in a 2-coordinate geometry to one O(3), one O(5), and two equivalent O(1) atoms. The K(2)-O(3) bond length is 2.66 Å. The K(2)-O(5) bond length is 2.63 Å. Both K(2)-O(1) bond lengths are 3.15 Å. In the third K site, K(3) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(4) atoms. The K(3)-O(1) bond length is 2.69 Å. Both K(3)-O(2) bond lengths are 2.96 Å. Both K(3)-O(4) bond lengths are 2.59 Å. In the fourth K site, K(4) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(4), and two equivalent O(5) atoms. The K(4)-O(3) bond length is 2.84 Å. Both K(4)-O(4) bond lengths are 2.66 Å. Both K(4)-O(5) bond lengths are 3.26 Å. Mg(1) is bonded in a trigonal planar geometry to one O(3) and two equivalent O(2) atoms. The Mg(1)-O(3) bond length is 1.94 Å. Both Mg(1)-O(2) bond lengths are 1.91 Å. There are two inequivalent V sites. In the first V site, V(1) is bonded to one O(1), one O(5), and two equivalent O(2) atoms to form corner-sharing VO4 tetrahedra. The V(1)-O(1) bond length is 1.76 Å. The V(1)-O(5) bond length is 1.89 Å. Both V(1)-O(2) bond lengths are 1.84 Å. In the second V site, V(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form corner-sharing VO4 tetrahedra. The V(2)-O(3) bond length is 1.93 Å. The V(2)-O(5) bond length is 1.91 Å. Both V(2)-O(4) bond lengths are 1.75 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to one K(1), one K(3), two equivalent K(2), and one V(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(3), one Mg(1), and one V(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(2), one K(4), two equivalent K(1), one Mg(1), and one V(2) atom. In the fourth O site, O(4) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one K(3), one K(4), and one V(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one K(2), two equivalent K(4), one V(1), and one V(2) atom.