Mn9FeO10 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedra are not tilted. In the second Mn site, Mn(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, edges with two equivalent Mn(5)O6 octahedra, and edges with three equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. In the third Mn site, Mn(3) is bonded to one O(1), two equivalent O(4), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedra are not tilted. In the fourth Mn site, Mn(4) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(5)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth Mn site, Mn(5) is bonded to one O(2), two equivalent O(4), and three equivalent O(5) atoms to form MnO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with three equivalent Mn(4)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with three equivalent Mn(4)O6 octahedra, and edges with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. Fe(1) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with two equivalent Mn(5)O6 octahedra, corners with four equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Mn(4)O6 octahedra, and edges with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mn(2), one Mn(3), two equivalent Mn(1), and two equivalent Mn(4) atoms to form OMn6 octahedra that share  a cornercorner with one O(3)Mn6 octahedra,  a cornercorner with one O(4)Mn6 octahedra, corners with two equivalent O(5)Mn5Fe octahedra, corners with two equivalent O(1)Mn6 octahedra,  an edgeedge with one O(5)Mn5Fe octahedra, edges with two equivalent O(2)Mn4Fe2 octahedra, edges with two equivalent O(4)Mn6 octahedra, edges with three equivalent O(1)Mn6 octahedra, and edges with four equivalent O(3)Mn6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second O site, O(2) is bonded to one Mn(4), one Mn(5), two equivalent Mn(2), and two equivalent Fe(1) atoms to form OMn4Fe2 octahedra that share  a cornercorner with one O(5)Mn5Fe octahedra,  a cornercorner with one O(4)Mn6 octahedra, corners with two equivalent O(2)Mn4Fe2 octahedra, corners with two equivalent O(3)Mn6 octahedra,  an edgeedge with one O(3)Mn6 octahedra, edges with two equivalent O(1)Mn6 octahedra, edges with two equivalent O(4)Mn6 octahedra, edges with three equivalent O(2)Mn4Fe2 octahedra, and edges with four equivalent O(5)Mn5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Mn(1), two equivalent Mn(2), and three equivalent Mn(3) atoms to form OMn6 octahedra that share  a cornercorner with one O(1)Mn6 octahedra,  a cornercorner with one O(3)Mn6 octahedra, corners with two equivalent O(2)Mn4Fe2 octahedra, corners with two equivalent O(4)Mn6 octahedra,  an edgeedge with one O(2)Mn4Fe2 octahedra, edges with three equivalent O(4)Mn6 octahedra, edges with four equivalent O(1)Mn6 octahedra, and edges with four equivalent O(3)Mn6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Mn(2), one Mn(4), two equivalent Mn(3), and two equivalent Mn(5) atoms to form OMn6 octahedra that share  a cornercorner with one O(2)Mn4Fe2 octahedra,  a cornercorner with one O(1)Mn6 octahedra, corners with two equivalent O(5)Mn5Fe octahedra, corners with two equivalent O(3)Mn6 octahedra, edges with two equivalent O(2)Mn4Fe2 octahedra, edges with two equivalent O(1)Mn6 octahedra, edges with two equivalent O(4)Mn6 octahedra, edges with three equivalent O(5)Mn5Fe octahedra, and edges with three equivalent O(3)Mn6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded to two equivalent Mn(4), three equivalent Mn(5), and one Fe(1) atom to form OMn5Fe octahedra that share  a cornercorner with one O(2)Mn4Fe2 octahedra,  a cornercorner with one O(5)Mn5Fe octahedra, corners with two equivalent O(1)Mn6 octahedra, corners with two equivalent O(4)Mn6 octahedra,  an edgeedge with one O(1)Mn6 octahedra, edges with three equivalent O(4)Mn6 octahedra, edges with four equivalent O(2)Mn4Fe2 octahedra, and edges with four equivalent O(5)Mn5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-1°.
Mn9FeO10 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are five inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedra are not tilted. Both Mn(1)-O(3) bond lengths are 2.27 Å. All Mn(1)-O(1) bond lengths are 2.26 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(4)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with three equivalent Mn(3)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, edges with two equivalent Mn(5)O6 octahedra, and edges with three equivalent Mn(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. The Mn(2)-O(1) bond length is 2.26 Å. The Mn(2)-O(4) bond length is 2.26 Å. Both Mn(2)-O(2) bond lengths are 2.28 Å. Both Mn(2)-O(3) bond lengths are 2.25 Å. In the third Mn site, Mn(3) is bonded to one O(1), two equivalent O(4), and three equivalent O(3) atoms to form a mixture of corner and edge-sharing MnO6 octahedra. The corner-sharing octahedra are not tilted. The Mn(3)-O(1) bond length is 2.27 Å. Both Mn(3)-O(4) bond lengths are 2.25 Å. All Mn(3)-O(3) bond lengths are 2.26 Å. In the fourth Mn site, Mn(4) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form MnO6 octahedra that share  a cornercorner with one Mn(2)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with three equivalent Mn(5)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(3)O6 octahedra, edges with two equivalent Mn(4)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, and edges with three equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Mn(4)-O(2) bond length is 2.26 Å. The Mn(4)-O(4) bond length is 2.28 Å. Both Mn(4)-O(1) bond lengths are 2.26 Å. Both Mn(4)-O(5) bond lengths are 2.24 Å. In the fifth Mn site, Mn(5) is bonded to one O(2), two equivalent O(4), and three equivalent O(5) atoms to form MnO6 octahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with two equivalent Mn(3)O6 octahedra, corners with three equivalent Mn(4)O6 octahedra,  an edgeedge with one Mn(3)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with three equivalent Mn(4)O6 octahedra, and edges with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Mn(5)-O(2) bond length is 2.26 Å. Both Mn(5)-O(4) bond lengths are 2.26 Å. There are two shorter (2.24 Å) and one longer (2.28 Å) Mn(5)-O(5) bond length. Fe(1) is bonded to two equivalent O(5) and four equivalent O(2) atoms to form FeO6 octahedra that share corners with two equivalent Mn(5)O6 octahedra, corners with four equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with four equivalent Mn(4)O6 octahedra, and edges with four equivalent Mn(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-2°. Both Fe(1)-O(5) bond lengths are 2.26 Å. All Fe(1)-O(2) bond lengths are 2.22 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Mn(2), one Mn(3), two equivalent Mn(1), and two equivalent Mn(4) atoms to form OMn6 octahedra that share  a cornercorner with one O(3)Mn6 octahedra,  a cornercorner with one O(4)Mn6 octahedra, corners with two equivalent O(5)Mn5Fe octahedra, corners with two equivalent O(1)Mn6 octahedra,  an edgeedge with one O(5)Mn5Fe octahedra, edges with two equivalent O(2)Mn4Fe2 octahedra, edges with two equivalent O(4)Mn6 octahedra, edges with three equivalent O(1)Mn6 octahedra, and edges with four equivalent O(3)Mn6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the second O site, O(2) is bonded to one Mn(4), one Mn(5), two equivalent Mn(2), and two equivalent Fe(1) atoms to form OMn4Fe2 octahedra that share  a cornercorner with one O(5)Mn5Fe octahedra,  a cornercorner with one O(4)Mn6 octahedra, corners with two equivalent O(2)Mn4Fe2 octahedra, corners with two equivalent O(3)Mn6 octahedra,  an edgeedge with one O(3)Mn6 octahedra, edges with two equivalent O(1)Mn6 octahedra, edges with two equivalent O(4)Mn6 octahedra, edges with three equivalent O(2)Mn4Fe2 octahedra, and edges with four equivalent O(5)Mn5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Mn(1), two equivalent Mn(2), and three equivalent Mn(3) atoms to form OMn6 octahedra that share  a cornercorner with one O(1)Mn6 octahedra,  a cornercorner with one O(3)Mn6 octahedra, corners with two equivalent O(2)Mn4Fe2 octahedra, corners with two equivalent O(4)Mn6 octahedra,  an edgeedge with one O(2)Mn4Fe2 octahedra, edges with three equivalent O(4)Mn6 octahedra, edges with four equivalent O(1)Mn6 octahedra, and edges with four equivalent O(3)Mn6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to one Mn(2), one Mn(4), two equivalent Mn(3), and two equivalent Mn(5) atoms to form OMn6 octahedra that share  a cornercorner with one O(2)Mn4Fe2 octahedra,  a cornercorner with one O(1)Mn6 octahedra, corners with two equivalent O(5)Mn5Fe octahedra, corners with two equivalent O(3)Mn6 octahedra, edges with two equivalent O(2)Mn4Fe2 octahedra, edges with two equivalent O(1)Mn6 octahedra, edges with two equivalent O(4)Mn6 octahedra, edges with three equivalent O(5)Mn5Fe octahedra, and edges with three equivalent O(3)Mn6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth O site, O(5) is bonded to two equivalent Mn(4), three equivalent Mn(5), and one Fe(1) atom to form OMn5Fe octahedra that share  a cornercorner with one O(2)Mn4Fe2 octahedra,  a cornercorner with one O(5)Mn5Fe octahedra, corners with two equivalent O(1)Mn6 octahedra, corners with two equivalent O(4)Mn6 octahedra,  an edgeedge with one O(1)Mn6 octahedra, edges with three equivalent O(4)Mn6 octahedra, edges with four equivalent O(2)Mn4Fe2 octahedra, and edges with four equivalent O(5)Mn5Fe octahedra. The corner-sharing octahedral tilt angles range from 0-1°.