MgEr6(GeS7)2 crystallizes in the trigonal P3 space group. Mg(1) is bonded in an octahedral geometry to three equivalent S(1) and three equivalent S(2) atoms. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one S(3), one S(6), two equivalent S(1), two equivalent S(2), and two equivalent S(5) atoms. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one S(4), one S(5), two equivalent S(1), two equivalent S(2), and two equivalent S(6) atoms. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a tetrahedral geometry to one S(3) and three equivalent S(5) atoms. In the second Ge site, Ge(2) is bonded in a tetrahedral geometry to one S(4) and three equivalent S(6) atoms. There are six inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Er(1), and two equivalent Er(2) atoms. In the second S site, S(2) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Er(1), and two equivalent Er(2) atoms. In the third S site, S(3) is bonded in a tetrahedral geometry to three equivalent Er(1) and one Ge(1) atom. In the fourth S site, S(4) is bonded in a tetrahedral geometry to three equivalent Er(2) and one Ge(2) atom. In the fifth S site, S(5) is bonded in a distorted rectangular see-saw-like geometry to one Er(2), two equivalent Er(1), and one Ge(1) atom. In the sixth S site, S(6) is bonded in a distorted rectangular see-saw-like geometry to one Er(1), two equivalent Er(2), and one Ge(2) atom.
MgEr6(GeS7)2 crystallizes in the trigonal P3 space group. Mg(1) is bonded in an octahedral geometry to three equivalent S(1) and three equivalent S(2) atoms. All Mg(1)-S(1) bond lengths are 2.59 Å. All Mg(1)-S(2) bond lengths are 2.55 Å. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one S(3), one S(6), two equivalent S(1), two equivalent S(2), and two equivalent S(5) atoms. The Er(1)-S(3) bond length is 2.86 Å. The Er(1)-S(6) bond length is 3.03 Å. There is one shorter (2.72 Å) and one longer (2.78 Å) Er(1)-S(1) bond length. There is one shorter (2.71 Å) and one longer (3.47 Å) Er(1)-S(2) bond length. There is one shorter (2.79 Å) and one longer (2.84 Å) Er(1)-S(5) bond length. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one S(4), one S(5), two equivalent S(1), two equivalent S(2), and two equivalent S(6) atoms. The Er(2)-S(4) bond length is 2.88 Å. The Er(2)-S(5) bond length is 3.01 Å. There is one shorter (2.76 Å) and one longer (3.39 Å) Er(2)-S(1) bond length. There is one shorter (2.69 Å) and one longer (2.78 Å) Er(2)-S(2) bond length. There is one shorter (2.81 Å) and one longer (2.86 Å) Er(2)-S(6) bond length. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a tetrahedral geometry to one S(3) and three equivalent S(5) atoms. The Ge(1)-S(3) bond length is 2.21 Å. All Ge(1)-S(5) bond lengths are 2.24 Å. In the second Ge site, Ge(2) is bonded in a tetrahedral geometry to one S(4) and three equivalent S(6) atoms. The Ge(2)-S(4) bond length is 2.22 Å. All Ge(2)-S(6) bond lengths are 2.24 Å. There are six inequivalent S sites. In the first S site, S(1) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Er(1), and two equivalent Er(2) atoms. In the second S site, S(2) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Er(1), and two equivalent Er(2) atoms. In the third S site, S(3) is bonded in a tetrahedral geometry to three equivalent Er(1) and one Ge(1) atom. In the fourth S site, S(4) is bonded in a tetrahedral geometry to three equivalent Er(2) and one Ge(2) atom. In the fifth S site, S(5) is bonded in a distorted rectangular see-saw-like geometry to one Er(2), two equivalent Er(1), and one Ge(1) atom. In the sixth S site, S(6) is bonded in a distorted rectangular see-saw-like geometry to one Er(1), two equivalent Er(2), and one Ge(2) atom.