Mn9(PO4)8 crystallizes in the triclinic P-1 space group. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(10), one O(14), one O(5), and one O(8) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 63-67°. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(14), one O(2), one O(3), and one O(9) atom to form distorted MnO6 octahedra that share  a cornercorner with one Mn(6)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent Mn(1)O5 trigonal bipyramids, and  an edgeedge with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the third Mn site, Mn(3) is bonded in a distorted square co-planar geometry to two equivalent O(1), two equivalent O(6), and two equivalent O(8) atoms. In the fourth Mn site, Mn(4) is bonded in a square co-planar geometry to two equivalent O(11) and two equivalent O(15) atoms. In the fifth Mn site, Mn(5) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(16), one O(4), one O(6), and one O(7) atom. In the sixth Mn site, Mn(6) is bonded to two equivalent O(12), two equivalent O(13), and two equivalent O(7) atoms to form distorted MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(13), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(1)O5 trigonal bipyramid, and  an edgeedge with one Mn(6)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. In the second P site, P(2) is bonded to one O(11), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(6)O6 octahedra and  a cornercorner with one Mn(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 40°. In the third P site, P(3) is bonded to one O(1), one O(15), one O(2), and one O(3) atom to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra and  a cornercorner with one Mn(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 43-50°. In the fourth P site, P(4) is bonded to one O(10), one O(14), one O(16), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(1)O5 trigonal bipyramids, and  an edgeedge with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(3), and one P(3) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(2) and one P(3) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Mn(5) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mn(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mn(3), one Mn(5), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mn(5), one Mn(6), and one P(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Mn(1), one Mn(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Mn(4) and one P(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mn(5), one Mn(6), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Mn(2), one Mn(6), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one P(4) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 120 degrees geometry to one Mn(4), one Mn(5), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a bent 120 degrees geometry to one Mn(5) and one P(4) atom.
Mn9(PO4)8 crystallizes in the triclinic P-1 space group. There are six inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(10), one O(14), one O(5), and one O(8) atom to form MnO5 trigonal bipyramids that share corners with two equivalent Mn(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(2)O4 tetrahedra,  a cornercorner with one P(3)O4 tetrahedra, and corners with two equivalent P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 63-67°. The Mn(1)-O(1) bond length is 2.25 Å. The Mn(1)-O(10) bond length is 1.99 Å. The Mn(1)-O(14) bond length is 2.09 Å. The Mn(1)-O(5) bond length is 1.98 Å. The Mn(1)-O(8) bond length is 2.00 Å. In the second Mn site, Mn(2) is bonded to one O(10), one O(13), one O(14), one O(2), one O(3), and one O(9) atom to form distorted MnO6 octahedra that share  a cornercorner with one Mn(6)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra,  a cornercorner with one P(4)O4 tetrahedra, corners with two equivalent P(3)O4 tetrahedra, corners with two equivalent Mn(1)O5 trigonal bipyramids, and  an edgeedge with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. The Mn(2)-O(10) bond length is 2.45 Å. The Mn(2)-O(13) bond length is 2.16 Å. The Mn(2)-O(14) bond length is 2.08 Å. The Mn(2)-O(2) bond length is 1.92 Å. The Mn(2)-O(3) bond length is 1.93 Å. The Mn(2)-O(9) bond length is 1.96 Å. In the third Mn site, Mn(3) is bonded in a distorted square co-planar geometry to two equivalent O(1), two equivalent O(6), and two equivalent O(8) atoms. Both Mn(3)-O(1) bond lengths are 2.08 Å. Both Mn(3)-O(6) bond lengths are 2.18 Å. Both Mn(3)-O(8) bond lengths are 2.70 Å. In the fourth Mn site, Mn(4) is bonded in a square co-planar geometry to two equivalent O(11) and two equivalent O(15) atoms. Both Mn(4)-O(11) bond lengths are 1.94 Å. Both Mn(4)-O(15) bond lengths are 1.94 Å. In the fifth Mn site, Mn(5) is bonded in a 6-coordinate geometry to one O(12), one O(15), one O(16), one O(4), one O(6), and one O(7) atom. The Mn(5)-O(12) bond length is 1.98 Å. The Mn(5)-O(15) bond length is 2.70 Å. The Mn(5)-O(16) bond length is 1.96 Å. The Mn(5)-O(4) bond length is 1.89 Å. The Mn(5)-O(6) bond length is 2.01 Å. The Mn(5)-O(7) bond length is 2.56 Å. In the sixth Mn site, Mn(6) is bonded to two equivalent O(12), two equivalent O(13), and two equivalent O(7) atoms to form distorted MnO6 octahedra that share corners with two equivalent Mn(2)O6 octahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. Both Mn(6)-O(12) bond lengths are 2.41 Å. Both Mn(6)-O(13) bond lengths are 2.27 Å. Both Mn(6)-O(7) bond lengths are 2.15 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(12), one O(13), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra,  a cornercorner with one Mn(1)O5 trigonal bipyramid, and  an edgeedge with one Mn(6)O6 octahedra. The corner-sharing octahedral tilt angles are 53°. The P(1)-O(12) bond length is 1.59 Å. The P(1)-O(13) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.50 Å. The P(1)-O(6) bond length is 1.59 Å. In the second P site, P(2) is bonded to one O(11), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(6)O6 octahedra and  a cornercorner with one Mn(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 40°. The P(2)-O(11) bond length is 1.56 Å. The P(2)-O(4) bond length is 1.56 Å. The P(2)-O(7) bond length is 1.55 Å. The P(2)-O(8) bond length is 1.56 Å. In the third P site, P(3) is bonded to one O(1), one O(15), one O(2), and one O(3) atom to form PO4 tetrahedra that share corners with two equivalent Mn(2)O6 octahedra and  a cornercorner with one Mn(1)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 43-50°. The P(3)-O(1) bond length is 1.55 Å. The P(3)-O(15) bond length is 1.56 Å. The P(3)-O(2) bond length is 1.54 Å. The P(3)-O(3) bond length is 1.55 Å. In the fourth P site, P(4) is bonded to one O(10), one O(14), one O(16), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(1)O5 trigonal bipyramids, and  an edgeedge with one Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles are 45°. The P(4)-O(10) bond length is 1.55 Å. The P(4)-O(14) bond length is 1.58 Å. The P(4)-O(16) bond length is 1.53 Å. The P(4)-O(9) bond length is 1.54 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(3), and one P(3) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(2) and one P(3) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(3) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Mn(5) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Mn(1) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mn(3), one Mn(5), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mn(5), one Mn(6), and one P(2) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one Mn(1), one Mn(3), and one P(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one P(4) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one Mn(1), one Mn(2), and one P(4) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Mn(4) and one P(2) atom. In the twelfth O site, O(12) is bonded in a 3-coordinate geometry to one Mn(5), one Mn(6), and one P(1) atom. In the thirteenth O site, O(13) is bonded in a distorted trigonal planar geometry to one Mn(2), one Mn(6), and one P(1) atom. In the fourteenth O site, O(14) is bonded in a distorted trigonal non-coplanar geometry to one Mn(1), one Mn(2), and one P(4) atom. In the fifteenth O site, O(15) is bonded in a distorted bent 120 degrees geometry to one Mn(4), one Mn(5), and one P(3) atom. In the sixteenth O site, O(16) is bonded in a bent 120 degrees geometry to one Mn(5) and one P(4) atom.