K2Sb4O11 crystallizes in the monoclinic C2/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(5), one O(6), and four equivalent O(2) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing SbO6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. In the second Sb site, Sb(2) is bonded to one O(6), one O(7), two equivalent O(3), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing SbO6 octahedra. The corner-sharing octahedral tilt angles range from 50-55°. In the third Sb site, Sb(3) is bonded to one O(1), one O(3), one O(5), one O(7), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing SbO6 octahedra. The corner-sharing octahedral tilt angles range from 32-47°. There are eight inequivalent O sites. In the first O site, O(3) is bonded in a distorted water-like geometry to two equivalent K(2), one Sb(2), and one Sb(3) atom. In the second O site, O(4) is bonded in a distorted water-like geometry to two equivalent K(2) and two equivalent Sb(1) atoms. In the third O site, O(5) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(2), and two equivalent Sb(3) atoms. In the fourth O site, O(6) is bonded in a distorted trigonal planar geometry to one K(1), one Sb(1), and one Sb(2) atom. In the fifth O site, O(7) is bonded in a distorted T-shaped geometry to one Sb(2) and two equivalent Sb(3) atoms. In the sixth O site, O(8) is bonded in a trigonal planar geometry to one Sb(1) and two equivalent Sb(2) atoms. In the seventh O site, O(1) is bonded in a distorted bent 120 degrees geometry to one K(2), one Sb(1), and one Sb(3) atom. In the eighth O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1) and two equivalent Sb(3) atoms.
K2Sb4O11 crystallizes in the monoclinic C2/m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 6-coordinate geometry to one O(5), one O(6), and four equivalent O(2) atoms. The K(1)-O(5) bond length is 3.06 Å. The K(1)-O(6) bond length is 2.82 Å. There are two shorter (2.89 Å) and two longer (3.22 Å) K(1)-O(2) bond lengths. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(5), two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms. The K(2)-O(5) bond length is 2.93 Å. Both K(2)-O(1) bond lengths are 3.32 Å. Both K(2)-O(4) bond lengths are 3.11 Å. There are two shorter (3.01 Å) and two longer (3.14 Å) K(2)-O(3) bond lengths. There are three inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing SbO6 octahedra. The corner-sharing octahedral tilt angles range from 47-55°. The Sb(1)-O(6) bond length is 1.96 Å. The Sb(1)-O(8) bond length is 2.08 Å. Both Sb(1)-O(1) bond lengths are 1.95 Å. Both Sb(1)-O(4) bond lengths are 2.00 Å. In the second Sb site, Sb(2) is bonded to one O(6), one O(7), two equivalent O(3), and two equivalent O(8) atoms to form a mixture of corner and edge-sharing SbO6 octahedra. The corner-sharing octahedral tilt angles range from 50-55°. The Sb(2)-O(6) bond length is 1.92 Å. The Sb(2)-O(7) bond length is 2.00 Å. Both Sb(2)-O(3) bond lengths are 1.98 Å. There is one shorter (1.98 Å) and one longer (2.12 Å) Sb(2)-O(8) bond length. In the third Sb site, Sb(3) is bonded to one O(1), one O(3), one O(5), one O(7), and two equivalent O(2) atoms to form a mixture of corner and edge-sharing SbO6 octahedra. The corner-sharing octahedral tilt angles range from 32-47°. The Sb(3)-O(1) bond length is 1.97 Å. The Sb(3)-O(3) bond length is 2.02 Å. The Sb(3)-O(5) bond length is 1.94 Å. The Sb(3)-O(7) bond length is 2.03 Å. Both Sb(3)-O(2) bond lengths are 1.99 Å. There are eight inequivalent O sites. In the first O site, O(3) is bonded in a distorted water-like geometry to two equivalent K(2), one Sb(2), and one Sb(3) atom. In the second O site, O(4) is bonded in a distorted water-like geometry to two equivalent K(2) and two equivalent Sb(1) atoms. In the third O site, O(5) is bonded in a distorted bent 150 degrees geometry to one K(1), one K(2), and two equivalent Sb(3) atoms. In the fourth O site, O(6) is bonded in a distorted trigonal planar geometry to one K(1), one Sb(1), and one Sb(2) atom. In the fifth O site, O(7) is bonded in a distorted T-shaped geometry to one Sb(2) and two equivalent Sb(3) atoms. In the sixth O site, O(8) is bonded in a trigonal planar geometry to one Sb(1) and two equivalent Sb(2) atoms. In the seventh O site, O(1) is bonded in a distorted bent 120 degrees geometry to one K(2), one Sb(1), and one Sb(3) atom. In the eighth O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1) and two equivalent Sb(3) atoms.