Er4MnS7 crystallizes in the monoclinic Cm space group. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to one S(4), two equivalent S(1), two equivalent S(3), and two equivalent S(6) atoms. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(2), two equivalent S(4), and two equivalent S(5) atoms. In the third Er site, Er(3) is bonded to one S(2), one S(6), two equivalent S(5), and two equivalent S(7) atoms to form ErS6 octahedra that share  a cornercorner with one Er(4)S6 octahedra, corners with two equivalent Mn(1)S6 octahedra, edges with two equivalent Er(3)S6 octahedra, and edges with three equivalent Mn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-52°. In the fourth Er site, Er(4) is bonded to one S(1), one S(2), two equivalent S(3), and two equivalent S(4) atoms to form ErS6 octahedra that share  a cornercorner with one Er(3)S6 octahedra,  a cornercorner with one Mn(1)S6 octahedra, and edges with two equivalent Er(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. Mn(1) is bonded to one S(1), one S(5), two equivalent S(6), and two equivalent S(7) atoms to form MnS6 octahedra that share  a cornercorner with one Er(4)S6 octahedra, corners with two equivalent Er(3)S6 octahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with three equivalent Er(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-55°. There are seven inequivalent S sites. In the first S site, S(1) is bonded to one Er(4), two equivalent Er(1), and one Mn(1) atom to form SEr3Mn tetrahedra that share  a cornercorner with one S(2)Er4 tetrahedra, corners with two equivalent S(1)Er3Mn tetrahedra,  a cornercorner with one S(5)Er4Mn trigonal bipyramid, corners with four equivalent S(6)Er3Mn2 trigonal bipyramids, corners with four equivalent S(3)Er5 trigonal bipyramids,  an edgeedge with one S(6)Er3Mn2 trigonal bipyramid,  an edgeedge with one S(3)Er5 trigonal bipyramid, and edges with two equivalent S(4)Er5 trigonal bipyramids. In the second S site, S(2) is bonded to one Er(3), one Er(4), and two equivalent Er(2) atoms to form SEr4 tetrahedra that share  a cornercorner with one S(1)Er3Mn tetrahedra, corners with two equivalent S(2)Er4 tetrahedra,  a cornercorner with one S(6)Er3Mn2 trigonal bipyramid, corners with four equivalent S(5)Er4Mn trigonal bipyramids, corners with four equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(5)Er4Mn trigonal bipyramid,  an edgeedge with one S(4)Er5 trigonal bipyramid, and edges with two equivalent S(3)Er5 trigonal bipyramids. In the third S site, S(3) is bonded to one Er(2), two equivalent Er(1), and two equivalent Er(4) atoms to form distorted SEr5 trigonal bipyramids that share corners with four equivalent S(1)Er3Mn tetrahedra, corners with two equivalent S(6)Er3Mn2 trigonal bipyramids, corners with two equivalent S(5)Er4Mn trigonal bipyramids, corners with two equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(1)Er3Mn tetrahedra, edges with two equivalent S(2)Er4 tetrahedra,  an edgeedge with one S(6)Er3Mn2 trigonal bipyramid, edges with two equivalent S(3)Er5 trigonal bipyramids, and edges with three equivalent S(4)Er5 trigonal bipyramids. In the fourth S site, S(4) is bonded to one Er(1), two equivalent Er(2), and two equivalent Er(4) atoms to form distorted SEr5 trigonal bipyramids that share corners with four equivalent S(2)Er4 tetrahedra, corners with two equivalent S(6)Er3Mn2 trigonal bipyramids, corners with two equivalent S(5)Er4Mn trigonal bipyramids, corners with two equivalent S(3)Er5 trigonal bipyramids,  an edgeedge with one S(2)Er4 tetrahedra, edges with two equivalent S(1)Er3Mn tetrahedra,  an edgeedge with one S(5)Er4Mn trigonal bipyramid, edges with two equivalent S(4)Er5 trigonal bipyramids, and edges with three equivalent S(3)Er5 trigonal bipyramids. In the fifth S site, S(5) is bonded to two equivalent Er(2), two equivalent Er(3), and one Mn(1) atom to form SEr4Mn trigonal bipyramids that share  a cornercorner with one S(1)Er3Mn tetrahedra, corners with four equivalent S(2)Er4 tetrahedra, corners with two equivalent S(3)Er5 trigonal bipyramids, corners with two equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(2)Er4 tetrahedra,  an edgeedge with one S(4)Er5 trigonal bipyramid, edges with two equivalent S(6)Er3Mn2 trigonal bipyramids, and edges with two equivalent S(5)Er4Mn trigonal bipyramids. In the sixth S site, S(6) is bonded to one Er(3), two equivalent Er(1), and two equivalent Mn(1) atoms to form SEr3Mn2 trigonal bipyramids that share  a cornercorner with one S(2)Er4 tetrahedra, corners with four equivalent S(1)Er3Mn tetrahedra, corners with two equivalent S(3)Er5 trigonal bipyramids, corners with two equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(1)Er3Mn tetrahedra,  an edgeedge with one S(3)Er5 trigonal bipyramid, edges with two equivalent S(6)Er3Mn2 trigonal bipyramids, and edges with two equivalent S(5)Er4Mn trigonal bipyramids. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to two equivalent Er(3) and two equivalent Mn(1) atoms.
Er4MnS7 crystallizes in the monoclinic Cm space group. There are four inequivalent Er sites. In the first Er site, Er(1) is bonded in a 7-coordinate geometry to one S(4), two equivalent S(1), two equivalent S(3), and two equivalent S(6) atoms. The Er(1)-S(4) bond length is 3.04 Å. Both Er(1)-S(1) bond lengths are 2.68 Å. Both Er(1)-S(3) bond lengths are 2.86 Å. Both Er(1)-S(6) bond lengths are 2.83 Å. In the second Er site, Er(2) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(2), two equivalent S(4), and two equivalent S(5) atoms. The Er(2)-S(3) bond length is 2.97 Å. Both Er(2)-S(2) bond lengths are 2.67 Å. Both Er(2)-S(4) bond lengths are 2.84 Å. Both Er(2)-S(5) bond lengths are 2.87 Å. In the third Er site, Er(3) is bonded to one S(2), one S(6), two equivalent S(5), and two equivalent S(7) atoms to form ErS6 octahedra that share  a cornercorner with one Er(4)S6 octahedra, corners with two equivalent Mn(1)S6 octahedra, edges with two equivalent Er(3)S6 octahedra, and edges with three equivalent Mn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-52°. The Er(3)-S(2) bond length is 2.69 Å. The Er(3)-S(6) bond length is 2.68 Å. Both Er(3)-S(5) bond lengths are 2.74 Å. Both Er(3)-S(7) bond lengths are 2.63 Å. In the fourth Er site, Er(4) is bonded to one S(1), one S(2), two equivalent S(3), and two equivalent S(4) atoms to form ErS6 octahedra that share  a cornercorner with one Er(3)S6 octahedra,  a cornercorner with one Mn(1)S6 octahedra, and edges with two equivalent Er(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 52-55°. The Er(4)-S(1) bond length is 2.63 Å. The Er(4)-S(2) bond length is 2.66 Å. Both Er(4)-S(3) bond lengths are 2.69 Å. Both Er(4)-S(4) bond lengths are 2.69 Å. Mn(1) is bonded to one S(1), one S(5), two equivalent S(6), and two equivalent S(7) atoms to form MnS6 octahedra that share  a cornercorner with one Er(4)S6 octahedra, corners with two equivalent Er(3)S6 octahedra, edges with two equivalent Mn(1)S6 octahedra, and edges with three equivalent Er(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 2-55°. The Mn(1)-S(1) bond length is 2.53 Å. The Mn(1)-S(5) bond length is 2.66 Å. Both Mn(1)-S(6) bond lengths are 2.63 Å. Both Mn(1)-S(7) bond lengths are 2.60 Å. There are seven inequivalent S sites. In the first S site, S(1) is bonded to one Er(4), two equivalent Er(1), and one Mn(1) atom to form SEr3Mn tetrahedra that share  a cornercorner with one S(2)Er4 tetrahedra, corners with two equivalent S(1)Er3Mn tetrahedra,  a cornercorner with one S(5)Er4Mn trigonal bipyramid, corners with four equivalent S(6)Er3Mn2 trigonal bipyramids, corners with four equivalent S(3)Er5 trigonal bipyramids,  an edgeedge with one S(6)Er3Mn2 trigonal bipyramid,  an edgeedge with one S(3)Er5 trigonal bipyramid, and edges with two equivalent S(4)Er5 trigonal bipyramids. In the second S site, S(2) is bonded to one Er(3), one Er(4), and two equivalent Er(2) atoms to form SEr4 tetrahedra that share  a cornercorner with one S(1)Er3Mn tetrahedra, corners with two equivalent S(2)Er4 tetrahedra,  a cornercorner with one S(6)Er3Mn2 trigonal bipyramid, corners with four equivalent S(5)Er4Mn trigonal bipyramids, corners with four equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(5)Er4Mn trigonal bipyramid,  an edgeedge with one S(4)Er5 trigonal bipyramid, and edges with two equivalent S(3)Er5 trigonal bipyramids. In the third S site, S(3) is bonded to one Er(2), two equivalent Er(1), and two equivalent Er(4) atoms to form distorted SEr5 trigonal bipyramids that share corners with four equivalent S(1)Er3Mn tetrahedra, corners with two equivalent S(6)Er3Mn2 trigonal bipyramids, corners with two equivalent S(5)Er4Mn trigonal bipyramids, corners with two equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(1)Er3Mn tetrahedra, edges with two equivalent S(2)Er4 tetrahedra,  an edgeedge with one S(6)Er3Mn2 trigonal bipyramid, edges with two equivalent S(3)Er5 trigonal bipyramids, and edges with three equivalent S(4)Er5 trigonal bipyramids. In the fourth S site, S(4) is bonded to one Er(1), two equivalent Er(2), and two equivalent Er(4) atoms to form distorted SEr5 trigonal bipyramids that share corners with four equivalent S(2)Er4 tetrahedra, corners with two equivalent S(6)Er3Mn2 trigonal bipyramids, corners with two equivalent S(5)Er4Mn trigonal bipyramids, corners with two equivalent S(3)Er5 trigonal bipyramids,  an edgeedge with one S(2)Er4 tetrahedra, edges with two equivalent S(1)Er3Mn tetrahedra,  an edgeedge with one S(5)Er4Mn trigonal bipyramid, edges with two equivalent S(4)Er5 trigonal bipyramids, and edges with three equivalent S(3)Er5 trigonal bipyramids. In the fifth S site, S(5) is bonded to two equivalent Er(2), two equivalent Er(3), and one Mn(1) atom to form SEr4Mn trigonal bipyramids that share  a cornercorner with one S(1)Er3Mn tetrahedra, corners with four equivalent S(2)Er4 tetrahedra, corners with two equivalent S(3)Er5 trigonal bipyramids, corners with two equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(2)Er4 tetrahedra,  an edgeedge with one S(4)Er5 trigonal bipyramid, edges with two equivalent S(6)Er3Mn2 trigonal bipyramids, and edges with two equivalent S(5)Er4Mn trigonal bipyramids. In the sixth S site, S(6) is bonded to one Er(3), two equivalent Er(1), and two equivalent Mn(1) atoms to form SEr3Mn2 trigonal bipyramids that share  a cornercorner with one S(2)Er4 tetrahedra, corners with four equivalent S(1)Er3Mn tetrahedra, corners with two equivalent S(3)Er5 trigonal bipyramids, corners with two equivalent S(4)Er5 trigonal bipyramids,  an edgeedge with one S(1)Er3Mn tetrahedra,  an edgeedge with one S(3)Er5 trigonal bipyramid, edges with two equivalent S(6)Er3Mn2 trigonal bipyramids, and edges with two equivalent S(5)Er4Mn trigonal bipyramids. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to two equivalent Er(3) and two equivalent Mn(1) atoms.