K2Cu(PO3)4 crystallizes in the monoclinic Cc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one O(11), one O(2), one O(5), one O(7), and one O(8) atom. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(12), one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(12), one O(4), and one O(9) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. In the second P site, P(2) is bonded to one O(11), one O(12), one O(6), and one O(7) atom to form corner-sharing PO4 tetrahedra. In the third P site, P(3) is bonded to one O(10), one O(11), one O(8), and one O(9) atom to form corner-sharing PO4 tetrahedra. In the fourth P site, P(4) is bonded to one O(1), one O(10), one O(2), and one O(3) atom to form corner-sharing PO4 tetrahedra. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one P(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(4) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(4) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(2), one Cu(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one K(2), one P(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one K(1), one K(2), and one P(3) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one K(2), one Cu(1), and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one P(3) and one P(4) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one K(1), one P(2), and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one K(2), one Cu(1), and one P(2) atom.
K2Cu(PO3)4 crystallizes in the monoclinic Cc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 5-coordinate geometry to one O(11), one O(2), one O(5), one O(7), and one O(8) atom. The K(1)-O(11) bond length is 2.98 Å. The K(1)-O(2) bond length is 2.72 Å. The K(1)-O(5) bond length is 2.81 Å. The K(1)-O(7) bond length is 2.73 Å. The K(1)-O(8) bond length is 2.81 Å. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(12), one O(2), one O(4), one O(5), one O(6), one O(7), one O(8), and one O(9) atom. The K(2)-O(12) bond length is 3.38 Å. The K(2)-O(2) bond length is 2.87 Å. The K(2)-O(4) bond length is 3.11 Å. The K(2)-O(5) bond length is 2.68 Å. The K(2)-O(6) bond length is 2.96 Å. The K(2)-O(7) bond length is 2.75 Å. The K(2)-O(8) bond length is 2.67 Å. The K(2)-O(9) bond length is 2.89 Å. Cu(1) is bonded in a distorted rectangular see-saw-like geometry to one O(1), one O(12), one O(4), and one O(9) atom. The Cu(1)-O(1) bond length is 1.97 Å. The Cu(1)-O(12) bond length is 1.97 Å. The Cu(1)-O(4) bond length is 1.96 Å. The Cu(1)-O(9) bond length is 2.01 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form corner-sharing PO4 tetrahedra. The P(1)-O(3) bond length is 1.62 Å. The P(1)-O(4) bond length is 1.51 Å. The P(1)-O(5) bond length is 1.49 Å. The P(1)-O(6) bond length is 1.63 Å. In the second P site, P(2) is bonded to one O(11), one O(12), one O(6), and one O(7) atom to form corner-sharing PO4 tetrahedra. The P(2)-O(11) bond length is 1.62 Å. The P(2)-O(12) bond length is 1.52 Å. The P(2)-O(6) bond length is 1.63 Å. The P(2)-O(7) bond length is 1.49 Å. In the third P site, P(3) is bonded to one O(10), one O(11), one O(8), and one O(9) atom to form corner-sharing PO4 tetrahedra. The P(3)-O(10) bond length is 1.61 Å. The P(3)-O(11) bond length is 1.63 Å. The P(3)-O(8) bond length is 1.49 Å. The P(3)-O(9) bond length is 1.51 Å. In the fourth P site, P(4) is bonded to one O(1), one O(10), one O(2), and one O(3) atom to form corner-sharing PO4 tetrahedra. The P(4)-O(1) bond length is 1.51 Å. The P(4)-O(10) bond length is 1.62 Å. The P(4)-O(2) bond length is 1.49 Å. The P(4)-O(3) bond length is 1.61 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 120 degrees geometry to one Cu(1) and one P(4) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(4) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one P(1) and one P(4) atom. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one K(2), one Cu(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(1) atom. In the sixth O site, O(6) is bonded in a 2-coordinate geometry to one K(2), one P(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(2) atom. In the eighth O site, O(8) is bonded in a distorted trigonal planar geometry to one K(1), one K(2), and one P(3) atom. In the ninth O site, O(9) is bonded in a 2-coordinate geometry to one K(2), one Cu(1), and one P(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one P(3) and one P(4) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one K(1), one P(2), and one P(3) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one K(2), one Cu(1), and one P(2) atom.