CaMn3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form MnO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  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(2), and two equivalent O(6) atoms to form MnO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Mn(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-62°. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-59°. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Mn(1), and one P(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(2), and one P(2) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Mn(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Mn(2), and one P(2) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Mn(1), one Mn(2), and one P(1) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Mn(1), and one P(1) atom. In the seventh O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.
CaMn3(P2O7)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a distorted body-centered cubic geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. Both Ca(1)-O(1) bond lengths are 2.49 Å. Both Ca(1)-O(2) bond lengths are 2.64 Å. Both Ca(1)-O(3) bond lengths are 2.64 Å. Both Ca(1)-O(5) bond lengths are 2.73 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), one O(3), one O(5), one O(6), and two equivalent O(7) atoms to form MnO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra,  an edgeedge with one Mn(1)O6 octahedra, and  an edgeedge with one Mn(2)O6 octahedra. The Mn(1)-O(2) bond length is 2.28 Å. The Mn(1)-O(3) bond length is 2.26 Å. The Mn(1)-O(5) bond length is 2.17 Å. The Mn(1)-O(6) bond length is 2.24 Å. Both Mn(1)-O(7) bond lengths are 2.18 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(6) atoms to form MnO6 octahedra that share corners with two equivalent P(1)O4 tetrahedra, corners with four equivalent P(2)O4 tetrahedra, and edges with two equivalent Mn(1)O6 octahedra. Both Mn(2)-O(1) bond lengths are 2.27 Å. Both Mn(2)-O(2) bond lengths are 2.23 Å. Both Mn(2)-O(6) bond lengths are 2.16 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 51-62°. The P(1)-O(2) bond length is 1.56 Å. The P(1)-O(3) bond length is 1.53 Å. The P(1)-O(4) bond length is 1.62 Å. The P(1)-O(5) bond length is 1.53 Å. In the second P site, P(2) is bonded to one O(1), one O(4), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 38-59°. The P(2)-O(1) bond length is 1.53 Å. The P(2)-O(4) bond length is 1.62 Å. The P(2)-O(6) bond length is 1.53 Å. The P(2)-O(7) bond length is 1.54 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Ca(1), one Mn(1), and one P(1) atom. In the second O site, O(6) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(2), and one P(2) atom. In the third O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Mn(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a distorted trigonal planar geometry to one Ca(1), one Mn(2), and one P(2) atom. In the fifth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), one Mn(1), one Mn(2), and one P(1) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1), one Mn(1), and one P(1) atom. In the seventh O site, O(4) is bonded in a bent 150 degrees geometry to one P(1) and one P(2) atom.