K3GeTe3 crystallizes in the monoclinic C2/c space group. There are four inequivalent K sites. In the first K site, K(1) is bonded to two equivalent Te(1), two equivalent Te(2), and two equivalent Te(3) atoms to form distorted KTe6 octahedra that share corners with two equivalent K(1)Te6 octahedra, corners with two equivalent Ge(1)GeTe3 tetrahedra, edges with two equivalent K(1)Te6 octahedra, and edges with two equivalent Ge(1)GeTe3 tetrahedra. The corner-sharing octahedral tilt angles are 38°. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent Te(1), two equivalent Te(2), and two equivalent Te(3) atoms. In the third K site, K(3) is bonded in a 6-coordinate geometry to two equivalent Te(1) and four equivalent Te(2) atoms. In the fourth K site, K(4) is bonded in a 6-coordinate geometry to two equivalent Te(1) and four equivalent Te(3) atoms. Ge(1) is bonded to one Ge(1), one Te(1), one Te(2), and one Te(3) atom to form GeGeTe3 tetrahedra that share corners with two equivalent K(1)Te6 octahedra,  a cornercorner with one Te(1)K6Ge pentagonal bipyramid,  a cornercorner with one Te(2)K6Ge pentagonal bipyramid,  a cornercorner with one Te(3)K6Ge pentagonal bipyramid, and edges with two equivalent K(1)Te6 octahedra. The corner-sharing octahedral tilt angles range from 81-82°. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded to one K(3), one K(4), two equivalent K(1), two equivalent K(2), and one Ge(1) atom to form distorted TeK6Ge pentagonal bipyramids that share corners with two equivalent Te(1)K6Ge pentagonal bipyramids, corners with four equivalent Te(2)K6Ge pentagonal bipyramids, corners with four equivalent Te(3)K6Ge pentagonal bipyramids,  a cornercorner with one Ge(1)GeTe3 tetrahedra, edges with two equivalent Te(1)K6Ge pentagonal bipyramids, edges with three equivalent Te(2)K6Ge pentagonal bipyramids, edges with three equivalent Te(3)K6Ge pentagonal bipyramids,  a faceface with one Te(2)K6Ge pentagonal bipyramid, and  a faceface with one Te(3)K6Ge pentagonal bipyramid. In the second Te site, Te(2) is bonded to two equivalent K(1), two equivalent K(2), two equivalent K(3), and one Ge(1) atom to form distorted TeK6Ge pentagonal bipyramids that share  a cornercorner with one Te(2)K6Ge pentagonal bipyramid, corners with two equivalent Te(3)K6Ge pentagonal bipyramids, corners with four equivalent Te(1)K6Ge pentagonal bipyramids,  a cornercorner with one Ge(1)GeTe3 tetrahedra, edges with two equivalent Te(3)K6Ge pentagonal bipyramids, edges with three equivalent Te(1)K6Ge pentagonal bipyramids, edges with three equivalent Te(2)K6Ge pentagonal bipyramids,  a faceface with one Te(1)K6Ge pentagonal bipyramid,  a faceface with one Te(2)K6Ge pentagonal bipyramid, and  a faceface with one Te(3)K6Ge pentagonal bipyramid. In the third Te site, Te(3) is bonded to two equivalent K(1), two equivalent K(2), two equivalent K(4), and one Ge(1) atom to form distorted TeK6Ge pentagonal bipyramids that share  a cornercorner with one Te(3)K6Ge pentagonal bipyramid, corners with two equivalent Te(2)K6Ge pentagonal bipyramids, corners with four equivalent Te(1)K6Ge pentagonal bipyramids,  a cornercorner with one Ge(1)GeTe3 tetrahedra, edges with two equivalent Te(2)K6Ge pentagonal bipyramids, edges with three equivalent Te(1)K6Ge pentagonal bipyramids, edges with three equivalent Te(3)K6Ge pentagonal bipyramids,  a faceface with one Te(1)K6Ge pentagonal bipyramid,  a faceface with one Te(2)K6Ge pentagonal bipyramid, and  a faceface with one Te(3)K6Ge pentagonal bipyramid.
K3GeTe3 crystallizes in the monoclinic C2/c space group. There are four inequivalent K sites. In the first K site, K(1) is bonded to two equivalent Te(1), two equivalent Te(2), and two equivalent Te(3) atoms to form distorted KTe6 octahedra that share corners with two equivalent K(1)Te6 octahedra, corners with two equivalent Ge(1)GeTe3 tetrahedra, edges with two equivalent K(1)Te6 octahedra, and edges with two equivalent Ge(1)GeTe3 tetrahedra. The corner-sharing octahedral tilt angles are 38°. There is one shorter (3.62 Å) and one longer (3.68 Å) K(1)-Te(1) bond length. There is one shorter (3.49 Å) and one longer (3.89 Å) K(1)-Te(2) bond length. There is one shorter (3.55 Å) and one longer (3.87 Å) K(1)-Te(3) bond length. In the second K site, K(2) is bonded in a 6-coordinate geometry to two equivalent Te(1), two equivalent Te(2), and two equivalent Te(3) atoms. There is one shorter (3.58 Å) and one longer (3.72 Å) K(2)-Te(1) bond length. There is one shorter (3.70 Å) and one longer (3.74 Å) K(2)-Te(2) bond length. There is one shorter (3.69 Å) and one longer (3.75 Å) K(2)-Te(3) bond length. In the third K site, K(3) is bonded in a 6-coordinate geometry to two equivalent Te(1) and four equivalent Te(2) atoms. Both K(3)-Te(1) bond lengths are 3.76 Å. There are two shorter (3.46 Å) and two longer (3.55 Å) K(3)-Te(2) bond lengths. In the fourth K site, K(4) is bonded in a 6-coordinate geometry to two equivalent Te(1) and four equivalent Te(3) atoms. Both K(4)-Te(1) bond lengths are 3.67 Å. There are two shorter (3.51 Å) and two longer (3.56 Å) K(4)-Te(3) bond lengths. Ge(1) is bonded to one Ge(1), one Te(1), one Te(2), and one Te(3) atom to form GeGeTe3 tetrahedra that share corners with two equivalent K(1)Te6 octahedra,  a cornercorner with one Te(1)K6Ge pentagonal bipyramid,  a cornercorner with one Te(2)K6Ge pentagonal bipyramid,  a cornercorner with one Te(3)K6Ge pentagonal bipyramid, and edges with two equivalent K(1)Te6 octahedra. The corner-sharing octahedral tilt angles range from 81-82°. The Ge(1)-Ge(1) bond length is 2.50 Å. The Ge(1)-Te(1) bond length is 2.61 Å. The Ge(1)-Te(2) bond length is 2.60 Å. The Ge(1)-Te(3) bond length is 2.58 Å. There are three inequivalent Te sites. In the first Te site, Te(1) is bonded to one K(3), one K(4), two equivalent K(1), two equivalent K(2), and one Ge(1) atom to form distorted TeK6Ge pentagonal bipyramids that share corners with two equivalent Te(1)K6Ge pentagonal bipyramids, corners with four equivalent Te(2)K6Ge pentagonal bipyramids, corners with four equivalent Te(3)K6Ge pentagonal bipyramids,  a cornercorner with one Ge(1)GeTe3 tetrahedra, edges with two equivalent Te(1)K6Ge pentagonal bipyramids, edges with three equivalent Te(2)K6Ge pentagonal bipyramids, edges with three equivalent Te(3)K6Ge pentagonal bipyramids,  a faceface with one Te(2)K6Ge pentagonal bipyramid, and  a faceface with one Te(3)K6Ge pentagonal bipyramid. In the second Te site, Te(2) is bonded to two equivalent K(1), two equivalent K(2), two equivalent K(3), and one Ge(1) atom to form distorted TeK6Ge pentagonal bipyramids that share  a cornercorner with one Te(2)K6Ge pentagonal bipyramid, corners with two equivalent Te(3)K6Ge pentagonal bipyramids, corners with four equivalent Te(1)K6Ge pentagonal bipyramids,  a cornercorner with one Ge(1)GeTe3 tetrahedra, edges with two equivalent Te(3)K6Ge pentagonal bipyramids, edges with three equivalent Te(1)K6Ge pentagonal bipyramids, edges with three equivalent Te(2)K6Ge pentagonal bipyramids,  a faceface with one Te(1)K6Ge pentagonal bipyramid,  a faceface with one Te(2)K6Ge pentagonal bipyramid, and  a faceface with one Te(3)K6Ge pentagonal bipyramid. In the third Te site, Te(3) is bonded to two equivalent K(1), two equivalent K(2), two equivalent K(4), and one Ge(1) atom to form distorted TeK6Ge pentagonal bipyramids that share  a cornercorner with one Te(3)K6Ge pentagonal bipyramid, corners with two equivalent Te(2)K6Ge pentagonal bipyramids, corners with four equivalent Te(1)K6Ge pentagonal bipyramids,  a cornercorner with one Ge(1)GeTe3 tetrahedra, edges with two equivalent Te(2)K6Ge pentagonal bipyramids, edges with three equivalent Te(1)K6Ge pentagonal bipyramids, edges with three equivalent Te(3)K6Ge pentagonal bipyramids,  a faceface with one Te(1)K6Ge pentagonal bipyramid,  a faceface with one Te(2)K6Ge pentagonal bipyramid, and  a faceface with one Te(3)K6Ge pentagonal bipyramid.