Ba4Ge2Te5Se3 crystallizes in the triclinic P1 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to one Te(1), one Te(3), one Te(5), two equivalent Te(2), one Se(1), one Se(2), and one Se(3) atom. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one Te(2), one Te(4), one Te(5), two equivalent Te(1), one Se(1), one Se(2), and one Se(3) atom. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one Te(1), one Te(3), one Te(5), two equivalent Te(4), one Se(1), one Se(2), and one Se(3) atom. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to one Te(2), one Te(4), one Te(5), two equivalent Te(3), one Se(1), one Se(2), and one Se(3) atom. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a distorted tetrahedral geometry to one Te(1), one Te(3), one Se(1), and one Se(2) atom. In the second Ge site, Ge(2) is bonded in a distorted tetrahedral geometry to one Te(2), one Te(4), one Te(5), and one Se(3) atom. There are five inequivalent Te sites. In the first Te site, Te(1) is bonded to one Ba(1), one Ba(3), two equivalent Ba(2), and one Ge(1) atom to form distorted TeBa4Ge trigonal bipyramids that share  a cornercorner with one Se(1)Ba4Ge square pyramid,  a cornercorner with one Se(2)Ba4Ge square pyramid, corners with four equivalent Te(5)Ba4Ge square pyramids, corners with four equivalent Se(3)Ba4Ge square pyramids,  a cornercorner with one Te(3)Ba4Ge trigonal bipyramid, corners with two equivalent Te(1)Ba4Ge trigonal bipyramids, edges with two equivalent Se(1)Ba4Ge square pyramids, edges with two equivalent Se(2)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(4)Ba4Ge trigonal bipyramids. In the second Te site, Te(2) is bonded to one Ba(2), one Ba(4), two equivalent Ba(1), and one Ge(2) atom to form distorted TeBa4Ge trigonal bipyramids that share  a cornercorner with one Te(5)Ba4Ge square pyramid,  a cornercorner with one Se(3)Ba4Ge square pyramid, corners with four equivalent Se(1)Ba4Ge square pyramids, corners with four equivalent Se(2)Ba4Ge square pyramids,  a cornercorner with one Te(4)Ba4Ge trigonal bipyramid, corners with two equivalent Te(2)Ba4Ge trigonal bipyramids, edges with two equivalent Te(5)Ba4Ge square pyramids, edges with two equivalent Se(3)Ba4Ge square pyramids,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(3)Ba4Ge trigonal bipyramids. In the third Te site, Te(3) is bonded to one Ba(1), one Ba(3), two equivalent Ba(4), and one Ge(1) atom to form distorted TeBa4Ge trigonal bipyramids that share corners with two equivalent Te(5)Ba4Ge square pyramids, corners with two equivalent Se(3)Ba4Ge square pyramids, corners with three equivalent Se(1)Ba4Ge square pyramids, corners with three equivalent Se(2)Ba4Ge square pyramids,  a cornercorner with one Te(1)Ba4Ge trigonal bipyramid, corners with two equivalent Te(3)Ba4Ge trigonal bipyramids,  an edgeedge with one Te(5)Ba4Ge square pyramid,  an edgeedge with one Se(1)Ba4Ge square pyramid,  an edgeedge with one Se(2)Ba4Ge square pyramid,  an edgeedge with one Se(3)Ba4Ge square pyramid,  an edgeedge with one Te(1)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(4)Ba4Ge trigonal bipyramids. In the fourth Te site, Te(4) is bonded to one Ba(2), one Ba(4), two equivalent Ba(3), and one Ge(2) atom to form distorted TeBa4Ge trigonal bipyramids that share corners with two equivalent Se(1)Ba4Ge square pyramids, corners with two equivalent Se(2)Ba4Ge square pyramids, corners with three equivalent Te(5)Ba4Ge square pyramids, corners with three equivalent Se(3)Ba4Ge square pyramids,  a cornercorner with one Te(2)Ba4Ge trigonal bipyramid, corners with two equivalent Te(4)Ba4Ge trigonal bipyramids,  an edgeedge with one Te(5)Ba4Ge square pyramid,  an edgeedge with one Se(1)Ba4Ge square pyramid,  an edgeedge with one Se(2)Ba4Ge square pyramid,  an edgeedge with one Se(3)Ba4Ge square pyramid,  an edgeedge with one Te(2)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(3)Ba4Ge trigonal bipyramids. In the fifth Te site, Te(5) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(2) atom to form TeBa4Ge square pyramids that share corners with four equivalent Se(1)Ba4Ge square pyramids,  a cornercorner with one Te(2)Ba4Ge trigonal bipyramid, corners with two equivalent Te(3)Ba4Ge trigonal bipyramids, corners with three equivalent Te(4)Ba4Ge trigonal bipyramids, corners with four equivalent Te(1)Ba4Ge trigonal bipyramids,  an edgeedge with one Se(3)Ba4Ge square pyramid, edges with two equivalent Se(2)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and  a faceface with one Se(3)Ba4Ge square pyramid. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(1) atom to form SeBa4Ge square pyramids that share corners with four equivalent Te(5)Ba4Ge square pyramids,  a cornercorner with one Te(1)Ba4Ge trigonal bipyramid, corners with two equivalent Te(4)Ba4Ge trigonal bipyramids, corners with three equivalent Te(3)Ba4Ge trigonal bipyramids, corners with four equivalent Te(2)Ba4Ge trigonal bipyramids,  an edgeedge with one Se(2)Ba4Ge square pyramid, edges with two equivalent Se(3)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and  a faceface with one Se(2)Ba4Ge square pyramid. In the second Se site, Se(2) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(1) atom to form distorted SeBa4Ge square pyramids that share corners with four equivalent Se(3)Ba4Ge square pyramids,  a cornercorner with one Te(1)Ba4Ge trigonal bipyramid, corners with two equivalent Te(4)Ba4Ge trigonal bipyramids, corners with three equivalent Te(3)Ba4Ge trigonal bipyramids, corners with four equivalent Te(2)Ba4Ge trigonal bipyramids,  an edgeedge with one Se(1)Ba4Ge square pyramid, edges with two equivalent Te(5)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and  a faceface with one Se(1)Ba4Ge square pyramid. In the third Se site, Se(3) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(2) atom to form distorted SeBa4Ge square pyramids that share corners with four equivalent Se(2)Ba4Ge square pyramids,  a cornercorner with one Te(2)Ba4Ge trigonal bipyramid, corners with two equivalent Te(3)Ba4Ge trigonal bipyramids, corners with three equivalent Te(4)Ba4Ge trigonal bipyramids, corners with four equivalent Te(1)Ba4Ge trigonal bipyramids,  an edgeedge with one Te(5)Ba4Ge square pyramid, edges with two equivalent Se(1)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and  a faceface with one Te(5)Ba4Ge square pyramid.
Ba4Ge2Te5Se3 crystallizes in the triclinic P1 space group. There are four inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to one Te(1), one Te(3), one Te(5), two equivalent Te(2), one Se(1), one Se(2), and one Se(3) atom. The Ba(1)-Te(1) bond length is 3.62 Å. The Ba(1)-Te(3) bond length is 3.76 Å. The Ba(1)-Te(5) bond length is 3.48 Å. There is one shorter (3.84 Å) and one longer (3.96 Å) Ba(1)-Te(2) bond length. The Ba(1)-Se(1) bond length is 3.39 Å. The Ba(1)-Se(2) bond length is 3.45 Å. The Ba(1)-Se(3) bond length is 3.38 Å. In the second Ba site, Ba(2) is bonded in a 8-coordinate geometry to one Te(2), one Te(4), one Te(5), two equivalent Te(1), one Se(1), one Se(2), and one Se(3) atom. The Ba(2)-Te(2) bond length is 3.67 Å. The Ba(2)-Te(4) bond length is 3.69 Å. The Ba(2)-Te(5) bond length is 3.51 Å. There is one shorter (3.84 Å) and one longer (3.94 Å) Ba(2)-Te(1) bond length. The Ba(2)-Se(1) bond length is 3.34 Å. The Ba(2)-Se(2) bond length is 3.40 Å. The Ba(2)-Se(3) bond length is 3.47 Å. In the third Ba site, Ba(3) is bonded in a 8-coordinate geometry to one Te(1), one Te(3), one Te(5), two equivalent Te(4), one Se(1), one Se(2), and one Se(3) atom. The Ba(3)-Te(1) bond length is 3.55 Å. The Ba(3)-Te(3) bond length is 3.64 Å. The Ba(3)-Te(5) bond length is 3.50 Å. There is one shorter (3.84 Å) and one longer (3.96 Å) Ba(3)-Te(4) bond length. The Ba(3)-Se(1) bond length is 3.46 Å. The Ba(3)-Se(2) bond length is 3.51 Å. The Ba(3)-Se(3) bond length is 3.42 Å. In the fourth Ba site, Ba(4) is bonded in a 8-coordinate geometry to one Te(2), one Te(4), one Te(5), two equivalent Te(3), one Se(1), one Se(2), and one Se(3) atom. The Ba(4)-Te(2) bond length is 3.59 Å. The Ba(4)-Te(4) bond length is 3.61 Å. The Ba(4)-Te(5) bond length is 3.55 Å. There is one shorter (3.85 Å) and one longer (3.94 Å) Ba(4)-Te(3) bond length. The Ba(4)-Se(1) bond length is 3.39 Å. The Ba(4)-Se(2) bond length is 3.44 Å. The Ba(4)-Se(3) bond length is 3.54 Å. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a distorted tetrahedral geometry to one Te(1), one Te(3), one Se(1), and one Se(2) atom. The Ge(1)-Te(1) bond length is 2.61 Å. The Ge(1)-Te(3) bond length is 2.60 Å. The Ge(1)-Se(1) bond length is 2.40 Å. The Ge(1)-Se(2) bond length is 2.39 Å. In the second Ge site, Ge(2) is bonded in a distorted tetrahedral geometry to one Te(2), one Te(4), one Te(5), and one Se(3) atom. The Ge(2)-Te(2) bond length is 2.61 Å. The Ge(2)-Te(4) bond length is 2.61 Å. The Ge(2)-Te(5) bond length is 2.60 Å. The Ge(2)-Se(3) bond length is 2.39 Å. There are five inequivalent Te sites. In the first Te site, Te(1) is bonded to one Ba(1), one Ba(3), two equivalent Ba(2), and one Ge(1) atom to form distorted TeBa4Ge trigonal bipyramids that share  a cornercorner with one Se(1)Ba4Ge square pyramid,  a cornercorner with one Se(2)Ba4Ge square pyramid, corners with four equivalent Te(5)Ba4Ge square pyramids, corners with four equivalent Se(3)Ba4Ge square pyramids,  a cornercorner with one Te(3)Ba4Ge trigonal bipyramid, corners with two equivalent Te(1)Ba4Ge trigonal bipyramids, edges with two equivalent Se(1)Ba4Ge square pyramids, edges with two equivalent Se(2)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(4)Ba4Ge trigonal bipyramids. In the second Te site, Te(2) is bonded to one Ba(2), one Ba(4), two equivalent Ba(1), and one Ge(2) atom to form distorted TeBa4Ge trigonal bipyramids that share  a cornercorner with one Te(5)Ba4Ge square pyramid,  a cornercorner with one Se(3)Ba4Ge square pyramid, corners with four equivalent Se(1)Ba4Ge square pyramids, corners with four equivalent Se(2)Ba4Ge square pyramids,  a cornercorner with one Te(4)Ba4Ge trigonal bipyramid, corners with two equivalent Te(2)Ba4Ge trigonal bipyramids, edges with two equivalent Te(5)Ba4Ge square pyramids, edges with two equivalent Se(3)Ba4Ge square pyramids,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(3)Ba4Ge trigonal bipyramids. In the third Te site, Te(3) is bonded to one Ba(1), one Ba(3), two equivalent Ba(4), and one Ge(1) atom to form distorted TeBa4Ge trigonal bipyramids that share corners with two equivalent Te(5)Ba4Ge square pyramids, corners with two equivalent Se(3)Ba4Ge square pyramids, corners with three equivalent Se(1)Ba4Ge square pyramids, corners with three equivalent Se(2)Ba4Ge square pyramids,  a cornercorner with one Te(1)Ba4Ge trigonal bipyramid, corners with two equivalent Te(3)Ba4Ge trigonal bipyramids,  an edgeedge with one Te(5)Ba4Ge square pyramid,  an edgeedge with one Se(1)Ba4Ge square pyramid,  an edgeedge with one Se(2)Ba4Ge square pyramid,  an edgeedge with one Se(3)Ba4Ge square pyramid,  an edgeedge with one Te(1)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(4)Ba4Ge trigonal bipyramids. In the fourth Te site, Te(4) is bonded to one Ba(2), one Ba(4), two equivalent Ba(3), and one Ge(2) atom to form distorted TeBa4Ge trigonal bipyramids that share corners with two equivalent Se(1)Ba4Ge square pyramids, corners with two equivalent Se(2)Ba4Ge square pyramids, corners with three equivalent Te(5)Ba4Ge square pyramids, corners with three equivalent Se(3)Ba4Ge square pyramids,  a cornercorner with one Te(2)Ba4Ge trigonal bipyramid, corners with two equivalent Te(4)Ba4Ge trigonal bipyramids,  an edgeedge with one Te(5)Ba4Ge square pyramid,  an edgeedge with one Se(1)Ba4Ge square pyramid,  an edgeedge with one Se(2)Ba4Ge square pyramid,  an edgeedge with one Se(3)Ba4Ge square pyramid,  an edgeedge with one Te(2)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and edges with two equivalent Te(3)Ba4Ge trigonal bipyramids. In the fifth Te site, Te(5) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(2) atom to form TeBa4Ge square pyramids that share corners with four equivalent Se(1)Ba4Ge square pyramids,  a cornercorner with one Te(2)Ba4Ge trigonal bipyramid, corners with two equivalent Te(3)Ba4Ge trigonal bipyramids, corners with three equivalent Te(4)Ba4Ge trigonal bipyramids, corners with four equivalent Te(1)Ba4Ge trigonal bipyramids,  an edgeedge with one Se(3)Ba4Ge square pyramid, edges with two equivalent Se(2)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and  a faceface with one Se(3)Ba4Ge square pyramid. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(1) atom to form SeBa4Ge square pyramids that share corners with four equivalent Te(5)Ba4Ge square pyramids,  a cornercorner with one Te(1)Ba4Ge trigonal bipyramid, corners with two equivalent Te(4)Ba4Ge trigonal bipyramids, corners with three equivalent Te(3)Ba4Ge trigonal bipyramids, corners with four equivalent Te(2)Ba4Ge trigonal bipyramids,  an edgeedge with one Se(2)Ba4Ge square pyramid, edges with two equivalent Se(3)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and  a faceface with one Se(2)Ba4Ge square pyramid. In the second Se site, Se(2) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(1) atom to form distorted SeBa4Ge square pyramids that share corners with four equivalent Se(3)Ba4Ge square pyramids,  a cornercorner with one Te(1)Ba4Ge trigonal bipyramid, corners with two equivalent Te(4)Ba4Ge trigonal bipyramids, corners with three equivalent Te(3)Ba4Ge trigonal bipyramids, corners with four equivalent Te(2)Ba4Ge trigonal bipyramids,  an edgeedge with one Se(1)Ba4Ge square pyramid, edges with two equivalent Te(5)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(1)Ba4Ge trigonal bipyramids, and  a faceface with one Se(1)Ba4Ge square pyramid. In the third Se site, Se(3) is bonded to one Ba(1), one Ba(2), one Ba(3), one Ba(4), and one Ge(2) atom to form distorted SeBa4Ge square pyramids that share corners with four equivalent Se(2)Ba4Ge square pyramids,  a cornercorner with one Te(2)Ba4Ge trigonal bipyramid, corners with two equivalent Te(3)Ba4Ge trigonal bipyramids, corners with three equivalent Te(4)Ba4Ge trigonal bipyramids, corners with four equivalent Te(1)Ba4Ge trigonal bipyramids,  an edgeedge with one Te(5)Ba4Ge square pyramid, edges with two equivalent Se(1)Ba4Ge square pyramids,  an edgeedge with one Te(3)Ba4Ge trigonal bipyramid,  an edgeedge with one Te(4)Ba4Ge trigonal bipyramid, edges with two equivalent Te(2)Ba4Ge trigonal bipyramids, and  a faceface with one Te(5)Ba4Ge square pyramid.