V3MnO8 crystallizes in the monoclinic Cm space group. There are three inequivalent V sites. In the first V site, V(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(8) atoms to form distorted VO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent V(1)O6 octahedra, and edges with two equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-26°. In the second V site, V(2) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. In the third V site, V(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and two equivalent O(7) atoms. Mn(1) is bonded to one O(5), one O(6), one O(7), one O(8), and two equivalent O(2) atoms to form distorted MnO6 octahedra that share  a cornercorner with one V(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, and edges with two equivalent V(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-27°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one V(3) and two equivalent V(2) atoms. In the second O site, O(2) is bonded to one V(1), one V(3), and two equivalent Mn(1) atoms to form distorted OMn2V2 trigonal pyramids that share corners with two equivalent O(2)Mn2V2 trigonal pyramids and edges with two equivalent O(7)MnV3 trigonal pyramids. In the third O site, O(3) is bonded in a linear geometry to one V(1) and one V(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one V(1), one V(2), and one V(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one V(1), one V(2), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to one V(2) and one Mn(1) atom. In the seventh O site, O(7) is bonded to one V(2), two equivalent V(3), and one Mn(1) atom to form distorted OMnV3 trigonal pyramids that share corners with two equivalent O(7)MnV3 trigonal pyramids and edges with two equivalent O(2)Mn2V2 trigonal pyramids. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to two equivalent V(1) and one Mn(1) atom.
V3MnO8 crystallizes in the monoclinic Cm space group. There are three inequivalent V sites. In the first V site, V(1) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(8) atoms to form distorted VO6 octahedra that share  a cornercorner with one Mn(1)O6 octahedra, corners with two equivalent V(1)O6 octahedra, and edges with two equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-26°. The V(1)-O(2) bond length is 2.07 Å. The V(1)-O(3) bond length is 1.96 Å. The V(1)-O(4) bond length is 2.13 Å. The V(1)-O(5) bond length is 1.75 Å. Both V(1)-O(8) bond lengths are 1.96 Å. In the second V site, V(2) is bonded in a 6-coordinate geometry to one O(4), one O(5), one O(6), one O(7), and two equivalent O(1) atoms. The V(2)-O(4) bond length is 1.80 Å. The V(2)-O(5) bond length is 2.32 Å. The V(2)-O(6) bond length is 1.65 Å. The V(2)-O(7) bond length is 2.03 Å. Both V(2)-O(1) bond lengths are 1.96 Å. In the third V site, V(3) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and two equivalent O(7) atoms. The V(3)-O(1) bond length is 1.97 Å. The V(3)-O(2) bond length is 2.32 Å. The V(3)-O(3) bond length is 1.71 Å. The V(3)-O(4) bond length is 2.01 Å. Both V(3)-O(7) bond lengths are 1.98 Å. Mn(1) is bonded to one O(5), one O(6), one O(7), one O(8), and two equivalent O(2) atoms to form distorted MnO6 octahedra that share  a cornercorner with one V(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, and edges with two equivalent V(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 21-27°. The Mn(1)-O(5) bond length is 1.97 Å. The Mn(1)-O(6) bond length is 2.12 Å. The Mn(1)-O(7) bond length is 2.27 Å. The Mn(1)-O(8) bond length is 1.92 Å. Both Mn(1)-O(2) bond lengths are 1.96 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one V(3) and two equivalent V(2) atoms. In the second O site, O(2) is bonded to one V(1), one V(3), and two equivalent Mn(1) atoms to form distorted OMn2V2 trigonal pyramids that share corners with two equivalent O(2)Mn2V2 trigonal pyramids and edges with two equivalent O(7)MnV3 trigonal pyramids. In the third O site, O(3) is bonded in a linear geometry to one V(1) and one V(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one V(1), one V(2), and one V(3) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one V(1), one V(2), and one Mn(1) atom. In the sixth O site, O(6) is bonded in a distorted linear geometry to one V(2) and one Mn(1) atom. In the seventh O site, O(7) is bonded to one V(2), two equivalent V(3), and one Mn(1) atom to form distorted OMnV3 trigonal pyramids that share corners with two equivalent O(7)MnV3 trigonal pyramids and edges with two equivalent O(2)Mn2V2 trigonal pyramids. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to two equivalent V(1) and one Mn(1) atom.