Er7Au2Te2 crystallizes in the monoclinic C2/m space group. There are eight inequivalent Er sites. In the first Er site, Er(1) is bonded in a 5-coordinate geometry to two equivalent Au(2), one Te(1), and two equivalent Te(2) atoms. In the second Er site, Er(2) is bonded in a 4-coordinate geometry to two equivalent Au(2) and two equivalent Te(2) atoms. In the third Er site, Er(3) is bonded in a 3-coordinate geometry to one Au(1), two equivalent Au(2), and one Te(2) atom. In the fourth Er site, Er(4) is bonded in a 4-coordinate geometry to three equivalent Au(1) and two equivalent Te(1) atoms. In the fifth Er site, Er(5) is bonded in a 4-coordinate geometry to two equivalent Au(1) and two equivalent Te(1) atoms. In the sixth Er site, Er(6) is bonded in a 5-coordinate geometry to two equivalent Au(1), one Te(1), and two equivalent Te(2) atoms. In the seventh Er site, Er(7) is bonded in a square co-planar geometry to two equivalent Au(2) and two equivalent Te(2) atoms. In the eighth Er site, Er(8) is bonded in a square co-planar geometry to two equivalent Au(1) and two equivalent Te(1) atoms. There are two inequivalent Au sites. In the first Au site, Au(1) is bonded in a 9-coordinate geometry to one Er(3), one Er(8), two equivalent Er(5), two equivalent Er(6), and three equivalent Er(4) atoms. In the second Au site, Au(2) is bonded in a 7-coordinate geometry to one Er(7), two equivalent Er(1), two equivalent Er(2), and two equivalent Er(3) atoms. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a 7-coordinate geometry to one Er(1), one Er(6), one Er(8), two equivalent Er(4), and two equivalent Er(5) atoms. In the second Te site, Te(2) is bonded in a 8-coordinate geometry to one Er(3), one Er(7), two equivalent Er(1), two equivalent Er(2), and two equivalent Er(6) atoms.
Er7Au2Te2 crystallizes in the monoclinic C2/m space group. There are eight inequivalent Er sites. In the first Er site, Er(1) is bonded in a 5-coordinate geometry to two equivalent Au(2), one Te(1), and two equivalent Te(2) atoms. Both Er(1)-Au(2) bond lengths are 2.89 Å. The Er(1)-Te(1) bond length is 3.06 Å. Both Er(1)-Te(2) bond lengths are 3.16 Å. In the second Er site, Er(2) is bonded in a 4-coordinate geometry to two equivalent Au(2) and two equivalent Te(2) atoms. Both Er(2)-Au(2) bond lengths are 2.98 Å. Both Er(2)-Te(2) bond lengths are 3.23 Å. In the third Er site, Er(3) is bonded in a 3-coordinate geometry to one Au(1), two equivalent Au(2), and one Te(2) atom. The Er(3)-Au(1) bond length is 3.47 Å. Both Er(3)-Au(2) bond lengths are 2.89 Å. The Er(3)-Te(2) bond length is 3.08 Å. In the fourth Er site, Er(4) is bonded in a 4-coordinate geometry to three equivalent Au(1) and two equivalent Te(1) atoms. There are two shorter (2.95 Å) and one longer (3.75 Å) Er(4)-Au(1) bond length. Both Er(4)-Te(1) bond lengths are 3.18 Å. In the fifth Er site, Er(5) is bonded in a 4-coordinate geometry to two equivalent Au(1) and two equivalent Te(1) atoms. Both Er(5)-Au(1) bond lengths are 2.95 Å. Both Er(5)-Te(1) bond lengths are 3.17 Å. In the sixth Er site, Er(6) is bonded in a 5-coordinate geometry to two equivalent Au(1), one Te(1), and two equivalent Te(2) atoms. Both Er(6)-Au(1) bond lengths are 2.90 Å. The Er(6)-Te(1) bond length is 3.05 Å. Both Er(6)-Te(2) bond lengths are 3.26 Å. In the seventh Er site, Er(7) is bonded in a square co-planar geometry to two equivalent Au(2) and two equivalent Te(2) atoms. Both Er(7)-Au(2) bond lengths are 3.04 Å. Both Er(7)-Te(2) bond lengths are 3.17 Å. In the eighth Er site, Er(8) is bonded in a square co-planar geometry to two equivalent Au(1) and two equivalent Te(1) atoms. Both Er(8)-Au(1) bond lengths are 3.18 Å. Both Er(8)-Te(1) bond lengths are 3.05 Å. There are two inequivalent Au sites. In the first Au site, Au(1) is bonded in a 9-coordinate geometry to one Er(3), one Er(8), two equivalent Er(5), two equivalent Er(6), and three equivalent Er(4) atoms. In the second Au site, Au(2) is bonded in a 7-coordinate geometry to one Er(7), two equivalent Er(1), two equivalent Er(2), and two equivalent Er(3) atoms. There are two inequivalent Te sites. In the first Te site, Te(1) is bonded in a 7-coordinate geometry to one Er(1), one Er(6), one Er(8), two equivalent Er(4), and two equivalent Er(5) atoms. In the second Te site, Te(2) is bonded in a 8-coordinate geometry to one Er(3), one Er(7), two equivalent Er(1), two equivalent Er(2), and two equivalent Er(6) atoms.