K8MgMn4O16 crystallizes in the triclinic P1 space group. There are eight inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(12), one O(2), one O(4), and two equivalent O(8) atoms. In the second K site, K(2) is bonded to one O(12), one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted KO7 pentagonal bipyramids that share  a cornercorner with one Mn(4)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(3)O4 tetrahedra, edges with two equivalent K(4)O6 octahedra, and  an edgeedge with one Mn(2)O4 tetrahedra. In the third K site, K(3) is bonded in a 6-coordinate geometry to one O(11), one O(16), one O(4), one O(6), and two equivalent O(14) atoms. In the fourth K site, K(4) is bonded to one O(1), one O(11), one O(3), one O(4), one O(7), and one O(8) atom to form KO6 octahedra that share  a cornercorner with one Mn(2)O4 tetrahedra,  a cornercorner with one Mn(4)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(3)O4 tetrahedra, and edges with two equivalent K(2)O7 pentagonal bipyramids. In the fifth K site, K(5) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(16), one O(6), and one O(9) atom. In the sixth K site, K(6) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(6), one O(7), and two equivalent O(3) atoms. In the seventh K site, K(7) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(14), one O(5), one O(6), and one O(9) atom. In the eighth K site, K(8) is bonded in a 7-coordinate geometry to one O(1), one O(13), one O(15), one O(2), one O(7), and two equivalent O(9) atoms. Mg(1) is bonded to one O(10), one O(14), one O(15), and one O(16) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one Mn(3)O4 tetrahedra,  a cornercorner with one Mn(4)O4 tetrahedra, and  an edgeedge with one Mn(4)O4 tetrahedra. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(7), and one O(9) atom to form MnO4 tetrahedra that share corners with two equivalent K(4)O6 octahedra and corners with two equivalent K(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 51-54°. In the second Mn site, Mn(2) is bonded to one O(13), one O(3), one O(5), and one O(6) atom to form MnO4 tetrahedra that share  a cornercorner with one K(4)O6 octahedra and  an edgeedge with one K(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 32°. In the third Mn site, Mn(3) is bonded to one O(11), one O(12), one O(14), and one O(4) atom to form MnO4 tetrahedra that share corners with two equivalent K(4)O6 octahedra, corners with two equivalent K(2)O7 pentagonal bipyramids, and  a cornercorner with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 26-43°. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(15), one O(16), and one O(8) atom to form MnO4 tetrahedra that share  a cornercorner with one K(4)O6 octahedra,  a cornercorner with one K(2)O7 pentagonal bipyramid,  a cornercorner with one Mg(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(4), one K(5), one K(8), and one Mn(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(8), and one Mn(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), one K(4), two equivalent K(6), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(3), one K(4), and one Mn(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(2), one K(7), and one Mn(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(3), one K(5), one K(6), one K(7), and one Mn(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(2), one K(4), one K(6), one K(8), and one Mn(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(2), one K(4), two equivalent K(1), and one Mn(4) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(5), one K(7), two equivalent K(8), and one Mn(1) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one K(1), one K(5), one Mg(1), and one Mn(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one K(1), one K(3), one K(4), one K(6), and one Mn(3) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(7), and one Mn(3) atom. In the thirteenth O site, O(13) is bonded in a distorted single-bond geometry to one K(5), one K(6), one K(7), one K(8), and one Mn(2) atom. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one K(7), two equivalent K(3), one Mg(1), and one Mn(3) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one K(8), one Mg(1), and one Mn(4) atom. In the sixteenth O site, O(16) is bonded in a distorted L-shaped geometry to one K(3), one K(5), one Mg(1), and one Mn(4) atom.
K8MgMn4O16 crystallizes in the triclinic P1 space group. There are eight inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(10), one O(11), one O(12), one O(2), one O(4), and two equivalent O(8) atoms. The K(1)-O(10) bond length is 2.93 Å. The K(1)-O(11) bond length is 3.28 Å. The K(1)-O(12) bond length is 3.14 Å. The K(1)-O(2) bond length is 2.80 Å. The K(1)-O(4) bond length is 2.89 Å. There is one shorter (2.81 Å) and one longer (3.11 Å) K(1)-O(8) bond length. In the second K site, K(2) is bonded to one O(12), one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form distorted KO7 pentagonal bipyramids that share  a cornercorner with one Mn(4)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(3)O4 tetrahedra, edges with two equivalent K(4)O6 octahedra, and  an edgeedge with one Mn(2)O4 tetrahedra. The K(2)-O(12) bond length is 2.75 Å. The K(2)-O(2) bond length is 2.86 Å. The K(2)-O(3) bond length is 2.86 Å. The K(2)-O(4) bond length is 2.76 Å. The K(2)-O(5) bond length is 2.84 Å. The K(2)-O(7) bond length is 3.06 Å. The K(2)-O(8) bond length is 2.98 Å. In the third K site, K(3) is bonded in a 6-coordinate geometry to one O(11), one O(16), one O(4), one O(6), and two equivalent O(14) atoms. The K(3)-O(11) bond length is 2.73 Å. The K(3)-O(16) bond length is 3.11 Å. The K(3)-O(4) bond length is 2.73 Å. The K(3)-O(6) bond length is 3.05 Å. There is one shorter (2.95 Å) and one longer (3.07 Å) K(3)-O(14) bond length. In the fourth K site, K(4) is bonded to one O(1), one O(11), one O(3), one O(4), one O(7), and one O(8) atom to form KO6 octahedra that share  a cornercorner with one Mn(2)O4 tetrahedra,  a cornercorner with one Mn(4)O4 tetrahedra, corners with two equivalent Mn(1)O4 tetrahedra, corners with two equivalent Mn(3)O4 tetrahedra, and edges with two equivalent K(2)O7 pentagonal bipyramids. The K(4)-O(1) bond length is 2.87 Å. The K(4)-O(11) bond length is 2.74 Å. The K(4)-O(3) bond length is 2.85 Å. The K(4)-O(4) bond length is 2.67 Å. The K(4)-O(7) bond length is 2.81 Å. The K(4)-O(8) bond length is 2.83 Å. In the fifth K site, K(5) is bonded in a 6-coordinate geometry to one O(1), one O(10), one O(13), one O(16), one O(6), and one O(9) atom. The K(5)-O(1) bond length is 2.85 Å. The K(5)-O(10) bond length is 2.79 Å. The K(5)-O(13) bond length is 2.65 Å. The K(5)-O(16) bond length is 2.88 Å. The K(5)-O(6) bond length is 2.62 Å. The K(5)-O(9) bond length is 2.65 Å. In the sixth K site, K(6) is bonded in a 6-coordinate geometry to one O(11), one O(13), one O(6), one O(7), and two equivalent O(3) atoms. The K(6)-O(11) bond length is 2.71 Å. The K(6)-O(13) bond length is 2.96 Å. The K(6)-O(6) bond length is 2.91 Å. The K(6)-O(7) bond length is 2.93 Å. There is one shorter (2.76 Å) and one longer (3.09 Å) K(6)-O(3) bond length. In the seventh K site, K(7) is bonded in a 6-coordinate geometry to one O(12), one O(13), one O(14), one O(5), one O(6), and one O(9) atom. The K(7)-O(12) bond length is 2.76 Å. The K(7)-O(13) bond length is 2.70 Å. The K(7)-O(14) bond length is 2.82 Å. The K(7)-O(5) bond length is 2.69 Å. The K(7)-O(6) bond length is 2.91 Å. The K(7)-O(9) bond length is 2.88 Å. In the eighth K site, K(8) is bonded in a 7-coordinate geometry to one O(1), one O(13), one O(15), one O(2), one O(7), and two equivalent O(9) atoms. The K(8)-O(1) bond length is 3.18 Å. The K(8)-O(13) bond length is 3.27 Å. The K(8)-O(15) bond length is 2.60 Å. The K(8)-O(2) bond length is 3.03 Å. The K(8)-O(7) bond length is 2.88 Å. There is one shorter (2.73 Å) and one longer (3.09 Å) K(8)-O(9) bond length. Mg(1) is bonded to one O(10), one O(14), one O(15), and one O(16) atom to form distorted MgO4 tetrahedra that share  a cornercorner with one Mn(3)O4 tetrahedra,  a cornercorner with one Mn(4)O4 tetrahedra, and  an edgeedge with one Mn(4)O4 tetrahedra. The Mg(1)-O(10) bond length is 1.98 Å. The Mg(1)-O(14) bond length is 1.91 Å. The Mg(1)-O(15) bond length is 2.00 Å. The Mg(1)-O(16) bond length is 2.04 Å. There are four inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(7), and one O(9) atom to form MnO4 tetrahedra that share corners with two equivalent K(4)O6 octahedra and corners with two equivalent K(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 51-54°. The Mn(1)-O(1) bond length is 1.67 Å. The Mn(1)-O(2) bond length is 1.65 Å. The Mn(1)-O(7) bond length is 1.67 Å. The Mn(1)-O(9) bond length is 1.68 Å. In the second Mn site, Mn(2) is bonded to one O(13), one O(3), one O(5), and one O(6) atom to form MnO4 tetrahedra that share  a cornercorner with one K(4)O6 octahedra and  an edgeedge with one K(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 32°. The Mn(2)-O(13) bond length is 1.67 Å. The Mn(2)-O(3) bond length is 1.67 Å. The Mn(2)-O(5) bond length is 1.65 Å. The Mn(2)-O(6) bond length is 1.67 Å. In the third Mn site, Mn(3) is bonded to one O(11), one O(12), one O(14), and one O(4) atom to form MnO4 tetrahedra that share corners with two equivalent K(4)O6 octahedra, corners with two equivalent K(2)O7 pentagonal bipyramids, and  a cornercorner with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 26-43°. The Mn(3)-O(11) bond length is 1.71 Å. The Mn(3)-O(12) bond length is 1.70 Å. The Mn(3)-O(14) bond length is 1.77 Å. The Mn(3)-O(4) bond length is 1.70 Å. In the fourth Mn site, Mn(4) is bonded to one O(10), one O(15), one O(16), and one O(8) atom to form MnO4 tetrahedra that share  a cornercorner with one K(4)O6 octahedra,  a cornercorner with one K(2)O7 pentagonal bipyramid,  a cornercorner with one Mg(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. The Mn(4)-O(10) bond length is 1.75 Å. The Mn(4)-O(15) bond length is 1.75 Å. The Mn(4)-O(16) bond length is 1.75 Å. The Mn(4)-O(8) bond length is 1.67 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(4), one K(5), one K(8), and one Mn(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(8), and one Mn(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), one K(4), two equivalent K(6), and one Mn(2) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(3), one K(4), and one Mn(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(2), one K(7), and one Mn(2) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one K(3), one K(5), one K(6), one K(7), and one Mn(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(2), one K(4), one K(6), one K(8), and one Mn(1) atom. In the eighth O site, O(8) is bonded in a distorted single-bond geometry to one K(2), one K(4), two equivalent K(1), and one Mn(4) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(5), one K(7), two equivalent K(8), and one Mn(1) atom. In the tenth O site, O(10) is bonded in a 2-coordinate geometry to one K(1), one K(5), one Mg(1), and one Mn(4) atom. In the eleventh O site, O(11) is bonded in a distorted single-bond geometry to one K(1), one K(3), one K(4), one K(6), and one Mn(3) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one K(1), one K(2), one K(7), and one Mn(3) atom. In the thirteenth O site, O(13) is bonded in a distorted single-bond geometry to one K(5), one K(6), one K(7), one K(8), and one Mn(2) atom. In the fourteenth O site, O(14) is bonded in a distorted linear geometry to one K(7), two equivalent K(3), one Mg(1), and one Mn(3) atom. In the fifteenth O site, O(15) is bonded in a 3-coordinate geometry to one K(8), one Mg(1), and one Mn(4) atom. In the sixteenth O site, O(16) is bonded in a distorted L-shaped geometry to one K(3), one K(5), one Mg(1), and one Mn(4) atom.