Ba2Er2Zn8O13 is Chalcostibite-derived structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(9), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(9), two equivalent O(5), two equivalent O(6), two equivalent O(8), and four equivalent O(4) atoms. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(8), two equivalent O(4), and two equivalent O(5) atoms to form ErO5 square pyramids that share  a cornercorner with one Zn(6)O4 tetrahedra, corners with two equivalent Zn(2)O4 tetrahedra, corners with two equivalent Zn(5)O4 tetrahedra, and corners with three equivalent Zn(4)O4 tetrahedra. In the second Er site, Er(2) is bonded to one O(7), one O(9), two equivalent O(3), and two equivalent O(6) atoms to form ErO6 octahedra that share  a cornercorner with one Zn(5)O4 tetrahedra, corners with two equivalent Zn(6)O4 tetrahedra, corners with three equivalent Zn(3)O4 tetrahedra, and corners with four equivalent Zn(2)O4 tetrahedra. There are six inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(5) atom. In the second Zn site, Zn(2) is bonded to one O(1), one O(4), one O(6), and one O(9) atom to form ZnO4 tetrahedra that share corners with two equivalent Er(2)O6 octahedra,  a cornercorner with one Er(1)O5 square pyramid,  a cornercorner with one Zn(3)O4 tetrahedra,  a cornercorner with one Zn(4)O4 tetrahedra, corners with two equivalent Zn(2)O4 tetrahedra, and corners with two equivalent Zn(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. In the third Zn site, Zn(3) is bonded to one O(1), one O(7), and two equivalent O(3) atoms to form ZnO4 tetrahedra that share corners with three equivalent Er(2)O6 octahedra,  a cornercorner with one Zn(5)O4 tetrahedra,  a cornercorner with one Zn(6)O4 tetrahedra, and corners with two equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-57°. In the fourth Zn site, Zn(4) is bonded to one O(2), one O(8), and two equivalent O(4) atoms to form ZnO4 tetrahedra that share corners with three equivalent Er(1)O5 square pyramids,  a cornercorner with one Zn(5)O4 tetrahedra,  a cornercorner with one Zn(6)O4 tetrahedra, and corners with two equivalent Zn(2)O4 tetrahedra. In the fifth Zn site, Zn(5) is bonded to one O(2), one O(7), and two equivalent O(5) atoms to form ZnO4 tetrahedra that share  a cornercorner with one Er(2)O6 octahedra, corners with two equivalent Er(1)O5 square pyramids,  a cornercorner with one Zn(3)O4 tetrahedra, and  a cornercorner with one Zn(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the sixth Zn site, Zn(6) is bonded to one O(1), one O(8), and two equivalent O(6) atoms to form ZnO4 tetrahedra that share corners with two equivalent Er(2)O6 octahedra,  a cornercorner with one Er(1)O5 square pyramid,  a cornercorner with one Zn(3)O4 tetrahedra,  a cornercorner with one Zn(4)O4 tetrahedra, and corners with four equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Zn(3), one Zn(6), and two equivalent Zn(2) atoms to form corner-sharing OZn4 tetrahedra. In the second O site, O(2) is bonded in a tetrahedral geometry to one Zn(4), one Zn(5), and two equivalent Zn(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Er(2), one Zn(1), and one Zn(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(2), one Er(1), one Zn(2), and one Zn(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Er(1), one Zn(1), and one Zn(5) atom. In the sixth O site, O(6) is bonded to one Ba(1), one Ba(2), one Er(2), one Zn(2), and one Zn(6) atom to form distorted OBa2ErZn2 trigonal bipyramids that share corners with two equivalent O(1)Zn4 tetrahedra, edges with two equivalent O(6)Ba2ErZn2 trigonal bipyramids, and edges with two equivalent O(9)Ba2ErZn2 trigonal bipyramids. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Ba(1), one Er(2), one Zn(3), and one Zn(5) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to two equivalent Ba(2), one Er(1), one Zn(4), and one Zn(6) atom. In the ninth O site, O(9) is bonded to one Ba(1), one Ba(2), one Er(2), and two equivalent Zn(2) atoms to form distorted OBa2ErZn2 trigonal bipyramids that share corners with two equivalent O(1)Zn4 tetrahedra and edges with four equivalent O(6)Ba2ErZn2 trigonal bipyramids.
Ba2Er2Zn8O13 is Chalcostibite-derived structured and crystallizes in the monoclinic Cm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 7-coordinate geometry to one O(9), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. The Ba(1)-O(9) bond length is 2.73 Å. Both Ba(1)-O(3) bond lengths are 2.95 Å. Both Ba(1)-O(6) bond lengths are 2.91 Å. Both Ba(1)-O(7) bond lengths are 3.24 Å. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(9), two equivalent O(5), two equivalent O(6), two equivalent O(8), and four equivalent O(4) atoms. The Ba(2)-O(9) bond length is 3.02 Å. Both Ba(2)-O(5) bond lengths are 3.32 Å. Both Ba(2)-O(6) bond lengths are 3.01 Å. Both Ba(2)-O(8) bond lengths are 3.21 Å. There are two shorter (3.13 Å) and two longer (3.33 Å) Ba(2)-O(4) bond lengths. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded to one O(8), two equivalent O(4), and two equivalent O(5) atoms to form ErO5 square pyramids that share  a cornercorner with one Zn(6)O4 tetrahedra, corners with two equivalent Zn(2)O4 tetrahedra, corners with two equivalent Zn(5)O4 tetrahedra, and corners with three equivalent Zn(4)O4 tetrahedra. The Er(1)-O(8) bond length is 2.06 Å. Both Er(1)-O(4) bond lengths are 2.21 Å. Both Er(1)-O(5) bond lengths are 2.26 Å. In the second Er site, Er(2) is bonded to one O(7), one O(9), two equivalent O(3), and two equivalent O(6) atoms to form ErO6 octahedra that share  a cornercorner with one Zn(5)O4 tetrahedra, corners with two equivalent Zn(6)O4 tetrahedra, corners with three equivalent Zn(3)O4 tetrahedra, and corners with four equivalent Zn(2)O4 tetrahedra. The Er(2)-O(7) bond length is 2.20 Å. The Er(2)-O(9) bond length is 2.27 Å. Both Er(2)-O(3) bond lengths are 2.30 Å. Both Er(2)-O(6) bond lengths are 2.24 Å. There are six inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a trigonal planar geometry to one O(2), one O(3), and one O(5) atom. The Zn(1)-O(2) bond length is 1.98 Å. The Zn(1)-O(3) bond length is 1.88 Å. The Zn(1)-O(5) bond length is 1.88 Å. In the second Zn site, Zn(2) is bonded to one O(1), one O(4), one O(6), and one O(9) atom to form ZnO4 tetrahedra that share corners with two equivalent Er(2)O6 octahedra,  a cornercorner with one Er(1)O5 square pyramid,  a cornercorner with one Zn(3)O4 tetrahedra,  a cornercorner with one Zn(4)O4 tetrahedra, corners with two equivalent Zn(2)O4 tetrahedra, and corners with two equivalent Zn(6)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. The Zn(2)-O(1) bond length is 1.99 Å. The Zn(2)-O(4) bond length is 1.98 Å. The Zn(2)-O(6) bond length is 1.99 Å. The Zn(2)-O(9) bond length is 1.99 Å. In the third Zn site, Zn(3) is bonded to one O(1), one O(7), and two equivalent O(3) atoms to form ZnO4 tetrahedra that share corners with three equivalent Er(2)O6 octahedra,  a cornercorner with one Zn(5)O4 tetrahedra,  a cornercorner with one Zn(6)O4 tetrahedra, and corners with two equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-57°. The Zn(3)-O(1) bond length is 1.98 Å. The Zn(3)-O(7) bond length is 1.97 Å. Both Zn(3)-O(3) bond lengths are 2.01 Å. In the fourth Zn site, Zn(4) is bonded to one O(2), one O(8), and two equivalent O(4) atoms to form ZnO4 tetrahedra that share corners with three equivalent Er(1)O5 square pyramids,  a cornercorner with one Zn(5)O4 tetrahedra,  a cornercorner with one Zn(6)O4 tetrahedra, and corners with two equivalent Zn(2)O4 tetrahedra. The Zn(4)-O(2) bond length is 2.02 Å. The Zn(4)-O(8) bond length is 1.99 Å. Both Zn(4)-O(4) bond lengths are 1.96 Å. In the fifth Zn site, Zn(5) is bonded to one O(2), one O(7), and two equivalent O(5) atoms to form ZnO4 tetrahedra that share  a cornercorner with one Er(2)O6 octahedra, corners with two equivalent Er(1)O5 square pyramids,  a cornercorner with one Zn(3)O4 tetrahedra, and  a cornercorner with one Zn(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. The Zn(5)-O(2) bond length is 2.01 Å. The Zn(5)-O(7) bond length is 1.95 Å. Both Zn(5)-O(5) bond lengths are 1.99 Å. In the sixth Zn site, Zn(6) is bonded to one O(1), one O(8), and two equivalent O(6) atoms to form ZnO4 tetrahedra that share corners with two equivalent Er(2)O6 octahedra,  a cornercorner with one Er(1)O5 square pyramid,  a cornercorner with one Zn(3)O4 tetrahedra,  a cornercorner with one Zn(4)O4 tetrahedra, and corners with four equivalent Zn(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. The Zn(6)-O(1) bond length is 1.98 Å. The Zn(6)-O(8) bond length is 1.97 Å. Both Zn(6)-O(6) bond lengths are 1.97 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Zn(3), one Zn(6), and two equivalent Zn(2) atoms to form corner-sharing OZn4 tetrahedra. In the second O site, O(2) is bonded in a tetrahedral geometry to one Zn(4), one Zn(5), and two equivalent Zn(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ba(1), one Er(2), one Zn(1), and one Zn(3) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to two equivalent Ba(2), one Er(1), one Zn(2), and one Zn(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Ba(2), one Er(1), one Zn(1), and one Zn(5) atom. In the sixth O site, O(6) is bonded to one Ba(1), one Ba(2), one Er(2), one Zn(2), and one Zn(6) atom to form distorted OBa2ErZn2 trigonal bipyramids that share corners with two equivalent O(1)Zn4 tetrahedra, edges with two equivalent O(6)Ba2ErZn2 trigonal bipyramids, and edges with two equivalent O(9)Ba2ErZn2 trigonal bipyramids. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to two equivalent Ba(1), one Er(2), one Zn(3), and one Zn(5) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to two equivalent Ba(2), one Er(1), one Zn(4), and one Zn(6) atom. In the ninth O site, O(9) is bonded to one Ba(1), one Ba(2), one Er(2), and two equivalent Zn(2) atoms to form distorted OBa2ErZn2 trigonal bipyramids that share corners with two equivalent O(1)Zn4 tetrahedra and edges with four equivalent O(6)Ba2ErZn2 trigonal bipyramids.