BaMnP2O7 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(6), two equivalent O(5), and three equivalent O(7) atoms. Mn(1) is bonded to one O(1), one O(5), one O(6), and two equivalent O(3) atoms to form MnO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Mn(1)O5 trigonal bipyramid. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Mn(1)O5 trigonal bipyramids. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Mn(1)O5 trigonal bipyramids. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ba(1), one Mn(1), and one P(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1) and one P(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ba(1), two equivalent Mn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ba(1), one Mn(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one P(1) atom.
BaMnP2O7 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one O(6), two equivalent O(5), and three equivalent O(7) atoms. The Ba(1)-O(1) bond length is 2.78 Å. The Ba(1)-O(2) bond length is 2.71 Å. The Ba(1)-O(3) bond length is 2.97 Å. The Ba(1)-O(6) bond length is 2.92 Å. There is one shorter (2.80 Å) and one longer (2.94 Å) Ba(1)-O(5) bond length. There are a spread of Ba(1)-O(7) bond distances ranging from 2.73-2.98 Å. Mn(1) is bonded to one O(1), one O(5), one O(6), and two equivalent O(3) atoms to form MnO5 trigonal bipyramids that share corners with two equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and  an edgeedge with one Mn(1)O5 trigonal bipyramid. The Mn(1)-O(1) bond length is 2.06 Å. The Mn(1)-O(5) bond length is 2.10 Å. The Mn(1)-O(6) bond length is 2.10 Å. There is one shorter (2.16 Å) and one longer (2.24 Å) Mn(1)-O(3) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with two equivalent Mn(1)O5 trigonal bipyramids. The P(1)-O(4) bond length is 1.61 Å. The P(1)-O(5) bond length is 1.53 Å. The P(1)-O(6) bond length is 1.52 Å. The P(1)-O(7) bond length is 1.50 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent Mn(1)O5 trigonal bipyramids. The P(2)-O(1) bond length is 1.52 Å. The P(2)-O(2) bond length is 1.48 Å. The P(2)-O(3) bond length is 1.55 Å. The P(2)-O(4) bond length is 1.61 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Ba(1), one Mn(1), and one P(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one Ba(1) and one P(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Ba(1), two equivalent Mn(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to two equivalent Ba(1), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one Ba(1), one Mn(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to three equivalent Ba(1) and one P(1) atom.