K2Mn3(AsO4)3 is Esseneite-like structured and crystallizes in the monoclinic C2/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms to form distorted KO8 hexagonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids,  an edgeedge with one Mn(2)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra,  an edgeedge with one As(2)O4 tetrahedra, and edges with two equivalent As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. In the second K site, K(2) is bonded in a distorted body-centered cubic geometry to four equivalent O(4) and four equivalent O(6) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(6), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids,  an edgeedge with one Mn(1)O6 octahedra, and  an edgeedge with one Mn(2)O6 octahedra. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted MnO6 octahedra that share corners with two equivalent K(1)O8 hexagonal bipyramids, corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra,  an edgeedge with one K(1)O8 hexagonal bipyramid, and edges with two equivalent Mn(1)O6 octahedra. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form AsO4 tetrahedra that share  a cornercorner with one K(1)O8 hexagonal bipyramid, corners with two equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 35-60°. In the second As site, As(2) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form AsO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 51-60°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one K(1), one Mn(1), one Mn(2), and one As(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one Mn(1), and one As(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Mn(1), one Mn(2), and one As(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent K(2), one Mn(2), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Mn(1) and one As(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent K(2), one Mn(1), and one As(2) atom.
K2Mn3(AsO4)3 is Esseneite-like structured and crystallizes in the monoclinic C2/c space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms to form distorted KO8 hexagonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids,  an edgeedge with one Mn(2)O6 octahedra, edges with four equivalent Mn(1)O6 octahedra,  an edgeedge with one As(2)O4 tetrahedra, and edges with two equivalent As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. Both K(1)-O(1) bond lengths are 2.89 Å. Both K(1)-O(3) bond lengths are 2.91 Å. There are two shorter (2.72 Å) and two longer (2.76 Å) K(1)-O(2) bond lengths. In the second K site, K(2) is bonded in a distorted body-centered cubic geometry to four equivalent O(4) and four equivalent O(6) atoms. There are two shorter (2.67 Å) and two longer (2.68 Å) K(2)-O(4) bond lengths. There are two shorter (2.57 Å) and two longer (3.01 Å) K(2)-O(6) bond lengths. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), one O(3), one O(6), and two equivalent O(5) atoms to form MnO6 octahedra that share corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra, edges with two equivalent K(1)O8 hexagonal bipyramids,  an edgeedge with one Mn(1)O6 octahedra, and  an edgeedge with one Mn(2)O6 octahedra. The Mn(1)-O(1) bond length is 2.20 Å. The Mn(1)-O(2) bond length is 2.06 Å. The Mn(1)-O(3) bond length is 2.14 Å. The Mn(1)-O(6) bond length is 1.96 Å. There is one shorter (2.11 Å) and one longer (2.25 Å) Mn(1)-O(5) bond length. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted MnO6 octahedra that share corners with two equivalent K(1)O8 hexagonal bipyramids, corners with two equivalent As(2)O4 tetrahedra, corners with four equivalent As(1)O4 tetrahedra,  an edgeedge with one K(1)O8 hexagonal bipyramid, and edges with two equivalent Mn(1)O6 octahedra. Both Mn(2)-O(1) bond lengths are 2.15 Å. Both Mn(2)-O(3) bond lengths are 2.31 Å. Both Mn(2)-O(4) bond lengths are 2.10 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form AsO4 tetrahedra that share  a cornercorner with one K(1)O8 hexagonal bipyramid, corners with two equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 35-60°. The As(1)-O(1) bond length is 1.71 Å. The As(1)-O(2) bond length is 1.70 Å. The As(1)-O(4) bond length is 1.68 Å. The As(1)-O(5) bond length is 1.72 Å. In the second As site, As(2) is bonded to two equivalent O(3) and two equivalent O(6) atoms to form AsO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with four equivalent Mn(1)O6 octahedra, and  an edgeedge with one K(1)O8 hexagonal bipyramid. The corner-sharing octahedral tilt angles range from 51-60°. Both As(2)-O(3) bond lengths are 1.72 Å. Both As(2)-O(6) bond lengths are 1.70 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one K(1), one Mn(1), one Mn(2), and one As(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one Mn(1), and one As(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one K(1), one Mn(1), one Mn(2), and one As(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent K(2), one Mn(2), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to two equivalent Mn(1) and one As(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to two equivalent K(2), one Mn(1), and one As(2) atom.