K3MnCPO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. In the second K site, K(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted KO7 pentagonal bipyramids that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent K(2)O7 pentagonal bipyramids, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one K(2)O7 pentagonal bipyramid,  an edgeedge with one P(1)O4 tetrahedra,  a faceface with one Mn(1)O6 octahedra, and  a faceface with one K(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 72°. Mn(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted MnO6 octahedra that share corners with two equivalent K(2)O7 pentagonal bipyramids, corners with four equivalent P(1)O4 tetrahedra, edges with two equivalent K(2)O7 pentagonal bipyramids, and faces with two equivalent K(2)O7 pentagonal bipyramids. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with four equivalent Mn(1)O6 octahedra, corners with four equivalent K(2)O7 pentagonal bipyramids, and edges with two equivalent K(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 32-43°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(2), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), one Mn(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), one Mn(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Mn(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(2), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(2), one Mn(1), and one P(1) atom.
K3MnCPO7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), two equivalent O(1), and two equivalent O(4) atoms. The K(1)-O(2) bond length is 2.79 Å. The K(1)-O(3) bond length is 2.85 Å. There is one shorter (2.82 Å) and one longer (2.88 Å) K(1)-O(1) bond length. Both K(1)-O(4) bond lengths are 2.79 Å. In the second K site, K(2) is bonded to one O(1), one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted KO7 pentagonal bipyramids that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent K(2)O7 pentagonal bipyramids, corners with two equivalent P(1)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra,  an edgeedge with one K(2)O7 pentagonal bipyramid,  an edgeedge with one P(1)O4 tetrahedra,  a faceface with one Mn(1)O6 octahedra, and  a faceface with one K(2)O7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 72°. The K(2)-O(1) bond length is 2.73 Å. The K(2)-O(2) bond length is 2.80 Å. The K(2)-O(3) bond length is 2.72 Å. The K(2)-O(5) bond length is 2.78 Å. The K(2)-O(6) bond length is 2.64 Å. There is one shorter (2.93 Å) and one longer (2.94 Å) K(2)-O(4) bond length. Mn(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(4) atoms to form distorted MnO6 octahedra that share corners with two equivalent K(2)O7 pentagonal bipyramids, corners with four equivalent P(1)O4 tetrahedra, edges with two equivalent K(2)O7 pentagonal bipyramids, and faces with two equivalent K(2)O7 pentagonal bipyramids. The Mn(1)-O(2) bond length is 2.33 Å. The Mn(1)-O(3) bond length is 2.40 Å. The Mn(1)-O(5) bond length is 2.11 Å. The Mn(1)-O(6) bond length is 2.13 Å. Both Mn(1)-O(4) bond lengths are 2.28 Å. C(1) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(3) atom. The C(1)-O(1) bond length is 1.30 Å. The C(1)-O(2) bond length is 1.31 Å. The C(1)-O(3) bond length is 1.31 Å. P(1) is bonded to one O(5), one O(6), and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with four equivalent Mn(1)O6 octahedra, corners with four equivalent K(2)O7 pentagonal bipyramids, and edges with two equivalent K(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 32-43°. The P(1)-O(5) bond length is 1.57 Å. The P(1)-O(6) bond length is 1.55 Å. Both P(1)-O(4) bond lengths are 1.56 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1), two equivalent K(2), and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), one Mn(1), and one C(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), one Mn(1), and one C(1) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one K(1), two equivalent K(2), one Mn(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to two equivalent K(2), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(2), one Mn(1), and one P(1) atom.