NbMn3(PO4)4 crystallizes in the monoclinic Pm space group. Nb(1) is bonded to one O(1), one O(9), two equivalent O(11), and two equivalent O(5) atoms to form distorted NbO6 pentagonal pyramids that share corners with four equivalent Mn(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-50°. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(12), one O(4), two equivalent O(2), and two equivalent O(8) atoms to form distorted MnO6 octahedra that share corners with four equivalent Mn(3)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-52°. In the second Mn site, Mn(2) is bonded to one O(3), one O(7), two equivalent O(11), and two equivalent O(5) atoms to form distorted MnO6 octahedra that share corners with four equivalent Nb(1)O6 pentagonal pyramids,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(4)O4 tetrahedra. In the third Mn site, Mn(3) is bonded to one O(10), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form distorted MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-52°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), and two equivalent O(2) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra,  a cornercorner with one Nb(1)O6 pentagonal pyramid, and  an edgeedge with one Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-55°. In the second P site, P(2) is bonded to one O(6), one O(9), and two equivalent O(5) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Nb(1)O6 pentagonal pyramid, and  an edgeedge with one Nb(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 32-63°. In the third P site, P(3) is bonded to one O(4), one O(7), and two equivalent O(8) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, and  an edgeedge with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-57°. In the fourth P site, P(4) is bonded to one O(12), one O(3), and two equivalent O(11) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Nb(1)O6 pentagonal pyramids, and  an edgeedge with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-46°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(3), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mn(2) and one P(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mn(1) and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Nb(1), one Mn(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mn(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(3), and one P(3) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(2) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Mn(3) and one P(1) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Nb(1), one Mn(2), and one P(4) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Mn(1) and one P(4) atom.
NbMn3(PO4)4 crystallizes in the monoclinic Pm space group. Nb(1) is bonded to one O(1), one O(9), two equivalent O(11), and two equivalent O(5) atoms to form distorted NbO6 pentagonal pyramids that share corners with four equivalent Mn(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-50°. The Nb(1)-O(1) bond length is 1.91 Å. The Nb(1)-O(9) bond length is 2.00 Å. Both Nb(1)-O(11) bond lengths are 2.03 Å. Both Nb(1)-O(5) bond lengths are 2.11 Å. There are three inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(12), one O(4), two equivalent O(2), and two equivalent O(8) atoms to form distorted MnO6 octahedra that share corners with four equivalent Mn(3)O6 octahedra,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(3)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-52°. The Mn(1)-O(12) bond length is 2.12 Å. The Mn(1)-O(4) bond length is 2.07 Å. Both Mn(1)-O(2) bond lengths are 2.18 Å. Both Mn(1)-O(8) bond lengths are 2.10 Å. In the second Mn site, Mn(2) is bonded to one O(3), one O(7), two equivalent O(11), and two equivalent O(5) atoms to form distorted MnO6 octahedra that share corners with four equivalent Nb(1)O6 pentagonal pyramids,  a cornercorner with one P(3)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and  an edgeedge with one P(4)O4 tetrahedra. The Mn(2)-O(3) bond length is 2.05 Å. The Mn(2)-O(7) bond length is 2.02 Å. Both Mn(2)-O(11) bond lengths are 2.40 Å. Both Mn(2)-O(5) bond lengths are 2.25 Å. In the third Mn site, Mn(3) is bonded to one O(10), one O(6), two equivalent O(2), and two equivalent O(8) atoms to form distorted MnO6 octahedra that share corners with four equivalent Mn(1)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, and  an edgeedge with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-52°. The Mn(3)-O(10) bond length is 2.03 Å. The Mn(3)-O(6) bond length is 2.08 Å. Both Mn(3)-O(2) bond lengths are 2.34 Å. Both Mn(3)-O(8) bond lengths are 2.17 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(10), and two equivalent O(2) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra,  a cornercorner with one Nb(1)O6 pentagonal pyramid, and  an edgeedge with one Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-55°. The P(1)-O(1) bond length is 1.64 Å. The P(1)-O(10) bond length is 1.51 Å. Both P(1)-O(2) bond lengths are 1.55 Å. In the second P site, P(2) is bonded to one O(6), one O(9), and two equivalent O(5) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(3)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one Nb(1)O6 pentagonal pyramid, and  an edgeedge with one Nb(1)O6 pentagonal pyramid. The corner-sharing octahedral tilt angles range from 32-63°. The P(2)-O(6) bond length is 1.48 Å. The P(2)-O(9) bond length is 1.55 Å. Both P(2)-O(5) bond lengths are 1.59 Å. In the third P site, P(3) is bonded to one O(4), one O(7), and two equivalent O(8) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, and  an edgeedge with one Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-57°. The P(3)-O(4) bond length is 1.51 Å. The P(3)-O(7) bond length is 1.53 Å. Both P(3)-O(8) bond lengths are 1.60 Å. In the fourth P site, P(4) is bonded to one O(12), one O(3), and two equivalent O(11) atoms to form PO4 tetrahedra that share  a cornercorner with one Mn(1)O6 octahedra,  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Nb(1)O6 pentagonal pyramids, and  an edgeedge with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-46°. The P(4)-O(12) bond length is 1.49 Å. The P(4)-O(3) bond length is 1.51 Å. Both P(4)-O(11) bond lengths are 1.63 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(3), and one P(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mn(2) and one P(4) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Mn(1) and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Nb(1), one Mn(2), and one P(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mn(3) and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(3) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one Mn(1), one Mn(3), and one P(3) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Nb(1) and one P(2) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Mn(3) and one P(1) atom. In the eleventh O site, O(11) is bonded in a 3-coordinate geometry to one Nb(1), one Mn(2), and one P(4) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Mn(1) and one P(4) atom.