Li5Mn3O8 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form LiO6 octahedra that share corners with six equivalent Mn(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 6°. In the second Li site, Li(2) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form LiO6 octahedra that share corners with three equivalent Li(3)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. In the third Li site, Li(3) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form LiO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. There are two 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 MnO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-11°. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(3), two equivalent Li(2), one Mn(1), and one Mn(2) atom to form OLi4Mn2 octahedra that share corners with six equivalent O(1)Li4Mn2 octahedra, edges with four equivalent O(3)Li3Mn3 octahedra, edges with four equivalent O(1)Li4Mn2 octahedra, and edges with four equivalent O(2)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second O site, O(2) is bonded to one Li(2), one Li(3), two equivalent Li(1), and two equivalent Mn(2) atoms to form OLi4Mn2 octahedra that share corners with three equivalent O(3)Li3Mn3 octahedra, corners with three equivalent O(2)Li4Mn2 octahedra,  an edgeedge with one O(2)Li4Mn2 octahedra, edges with three equivalent O(3)Li3Mn3 octahedra, and edges with eight equivalent O(1)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), one Mn(1), and two equivalent Mn(2) atoms to form OLi3Mn3 octahedra that share corners with three equivalent O(3)Li3Mn3 octahedra, corners with three equivalent O(2)Li4Mn2 octahedra,  an edgeedge with one O(3)Li3Mn3 octahedra, edges with three equivalent O(2)Li4Mn2 octahedra, and edges with eight equivalent O(1)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.
Li5Mn3O8 is Caswellsilverite-like structured and crystallizes in the monoclinic C2/m space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form LiO6 octahedra that share corners with six equivalent Mn(2)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 6°. Both Li(1)-O(1) bond lengths are 2.31 Å. Both Li(1)-O(2) bond lengths are 2.15 Å. Both Li(1)-O(3) bond lengths are 2.13 Å. In the second Li site, Li(2) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form LiO6 octahedra that share corners with three equivalent Li(3)O6 octahedra, corners with three equivalent Mn(1)O6 octahedra,  an edgeedge with one Li(3)O6 octahedra,  an edgeedge with one Mn(1)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. The Li(2)-O(2) bond length is 2.08 Å. The Li(2)-O(3) bond length is 2.06 Å. There are two shorter (2.10 Å) and two longer (2.12 Å) Li(2)-O(1) bond lengths. In the third Li site, Li(3) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form LiO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-12°. Both Li(3)-O(2) bond lengths are 2.18 Å. All Li(3)-O(1) bond lengths are 2.04 Å. There are two 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 MnO6 octahedra that share corners with six equivalent Li(2)O6 octahedra, edges with two equivalent Li(2)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with four equivalent Li(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-11°. Both Mn(1)-O(3) bond lengths are 2.19 Å. All Mn(1)-O(1) bond lengths are 1.96 Å. In the second Mn site, Mn(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MnO6 octahedra that share corners with six equivalent Li(1)O6 octahedra, edges with two equivalent Li(1)O6 octahedra, edges with two equivalent Li(3)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, and edges with four equivalent Li(2)O6 octahedra. The corner-sharing octahedral tilt angles are 6°. Both Mn(2)-O(1) bond lengths are 1.94 Å. Both Mn(2)-O(2) bond lengths are 1.93 Å. Both Mn(2)-O(3) bond lengths are 1.98 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Li(1), one Li(3), two equivalent Li(2), one Mn(1), and one Mn(2) atom to form OLi4Mn2 octahedra that share corners with six equivalent O(1)Li4Mn2 octahedra, edges with four equivalent O(3)Li3Mn3 octahedra, edges with four equivalent O(1)Li4Mn2 octahedra, and edges with four equivalent O(2)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-4°. In the second O site, O(2) is bonded to one Li(2), one Li(3), two equivalent Li(1), and two equivalent Mn(2) atoms to form OLi4Mn2 octahedra that share corners with three equivalent O(3)Li3Mn3 octahedra, corners with three equivalent O(2)Li4Mn2 octahedra,  an edgeedge with one O(2)Li4Mn2 octahedra, edges with three equivalent O(3)Li3Mn3 octahedra, and edges with eight equivalent O(1)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Li(2), two equivalent Li(1), one Mn(1), and two equivalent Mn(2) atoms to form OLi3Mn3 octahedra that share corners with three equivalent O(3)Li3Mn3 octahedra, corners with three equivalent O(2)Li4Mn2 octahedra,  an edgeedge with one O(3)Li3Mn3 octahedra, edges with three equivalent O(2)Li4Mn2 octahedra, and edges with eight equivalent O(1)Li4Mn2 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.