KBiP2S7 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one S(6), one S(7), two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms. Bi(1) is bonded to one S(1), one S(2), one S(3), one S(5), one S(7), and two equivalent S(4) atoms to form distorted BiS7 pentagonal bipyramids that share corners with two equivalent Bi(1)S7 pentagonal bipyramids,  a cornercorner with one P(2)S4 tetrahedra,  an edgeedge with one P(2)S4 tetrahedra, and edges with two equivalent P(1)S4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one S(2), one S(4), one S(6), and one S(7) atom to form PS4 tetrahedra that share  a cornercorner with one P(2)S4 tetrahedra and edges with two equivalent Bi(1)S7 pentagonal bipyramids. In the second P site, P(2) is bonded to one S(1), one S(3), one S(5), and one S(6) atom to form PS4 tetrahedra that share  a cornercorner with one Bi(1)S7 pentagonal bipyramid,  a cornercorner with one P(1)S4 tetrahedra, and  an edgeedge with one Bi(1)S7 pentagonal bipyramid. There are seven inequivalent S sites. In the first S site, S(5) is bonded in an L-shaped geometry to one Bi(1) and one P(2) atom. In the second S site, S(6) is bonded in a distorted bent 120 degrees geometry to one K(1), one P(1), and one P(2) atom. In the third S site, S(7) is bonded in a distorted T-shaped geometry to one K(1), one Bi(1), and one P(1) atom. In the fourth S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(1), one Bi(1), and one P(2) atom. In the fifth S site, S(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one Bi(1), and one P(1) atom. In the sixth S site, S(3) is bonded in a 4-coordinate geometry to two equivalent K(1), one Bi(1), and one P(2) atom. In the seventh S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Bi(1) and one P(1) atom.
KBiP2S7 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one S(6), one S(7), two equivalent S(1), two equivalent S(2), and two equivalent S(3) atoms. The K(1)-S(6) bond length is 3.70 Å. The K(1)-S(7) bond length is 3.52 Å. There is one shorter (3.41 Å) and one longer (3.47 Å) K(1)-S(1) bond length. There is one shorter (3.38 Å) and one longer (3.41 Å) K(1)-S(2) bond length. There is one shorter (3.39 Å) and one longer (3.47 Å) K(1)-S(3) bond length. Bi(1) is bonded to one S(1), one S(2), one S(3), one S(5), one S(7), and two equivalent S(4) atoms to form distorted BiS7 pentagonal bipyramids that share corners with two equivalent Bi(1)S7 pentagonal bipyramids,  a cornercorner with one P(2)S4 tetrahedra,  an edgeedge with one P(2)S4 tetrahedra, and edges with two equivalent P(1)S4 tetrahedra. The Bi(1)-S(1) bond length is 3.08 Å. The Bi(1)-S(2) bond length is 2.93 Å. The Bi(1)-S(3) bond length is 2.82 Å. The Bi(1)-S(5) bond length is 2.87 Å. The Bi(1)-S(7) bond length is 2.82 Å. There is one shorter (2.91 Å) and one longer (3.06 Å) Bi(1)-S(4) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one S(2), one S(4), one S(6), and one S(7) atom to form PS4 tetrahedra that share  a cornercorner with one P(2)S4 tetrahedra and edges with two equivalent Bi(1)S7 pentagonal bipyramids. The P(1)-S(2) bond length is 2.03 Å. The P(1)-S(4) bond length is 2.04 Å. The P(1)-S(6) bond length is 2.15 Å. The P(1)-S(7) bond length is 2.05 Å. In the second P site, P(2) is bonded to one S(1), one S(3), one S(5), and one S(6) atom to form PS4 tetrahedra that share  a cornercorner with one Bi(1)S7 pentagonal bipyramid,  a cornercorner with one P(1)S4 tetrahedra, and  an edgeedge with one Bi(1)S7 pentagonal bipyramid. The P(2)-S(1) bond length is 2.02 Å. The P(2)-S(3) bond length is 2.05 Å. The P(2)-S(5) bond length is 2.04 Å. The P(2)-S(6) bond length is 2.14 Å. There are seven inequivalent S sites. In the first S site, S(5) is bonded in an L-shaped geometry to one Bi(1) and one P(2) atom. In the second S site, S(6) is bonded in a distorted bent 120 degrees geometry to one K(1), one P(1), and one P(2) atom. In the third S site, S(7) is bonded in a distorted T-shaped geometry to one K(1), one Bi(1), and one P(1) atom. In the fourth S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(1), one Bi(1), and one P(2) atom. In the fifth S site, S(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one Bi(1), and one P(1) atom. In the sixth S site, S(3) is bonded in a 4-coordinate geometry to two equivalent K(1), one Bi(1), and one P(2) atom. In the seventh S site, S(4) is bonded in a 3-coordinate geometry to two equivalent Bi(1) and one P(1) atom.