K4P4O5 crystallizes in the monoclinic P2_1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 4-coordinate geometry to one P(4), one O(1), one O(3), one O(4), and one O(5) atom. In the second K site, K(2) is bonded in a 5-coordinate geometry to one P(4), one O(1), one O(2), one O(3), and one O(4) atom. In the third K site, K(3) is bonded in a 3-coordinate geometry to two equivalent P(4), one O(1), one O(2), and one O(5) atom. In the fourth K site, K(4) is bonded in a 3-coordinate geometry to one P(4), one O(2), one O(3), and one O(4) atom. There are four inequivalent P sites. In the first P site, P(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. In the second P site, P(2) is bonded in a single-bond geometry to one P(4) and one O(5) atom. In the third P site, P(3) is bonded in a single-bond geometry to one O(4) atom. In the fourth P site, P(4) is bonded in a 6-coordinate geometry to one K(1), one K(2), one K(4), two equivalent K(3), and one P(2) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(3), and one P(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one K(2), one K(3), one K(4), and one P(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(4), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one K(1), one K(2), one K(4), one P(1), and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(3), and one P(2) atom.
K4P4O5 crystallizes in the monoclinic P2_1 space group. There are four inequivalent K sites. In the first K site, K(1) is bonded in a 4-coordinate geometry to one P(4), one O(1), one O(3), one O(4), and one O(5) atom. The K(1)-P(4) bond length is 3.51 Å. The K(1)-O(1) bond length is 2.63 Å. The K(1)-O(3) bond length is 3.20 Å. The K(1)-O(4) bond length is 2.86 Å. The K(1)-O(5) bond length is 2.81 Å. In the second K site, K(2) is bonded in a 5-coordinate geometry to one P(4), one O(1), one O(2), one O(3), and one O(4) atom. The K(2)-P(4) bond length is 3.43 Å. The K(2)-O(1) bond length is 3.17 Å. The K(2)-O(2) bond length is 3.01 Å. The K(2)-O(3) bond length is 2.65 Å. The K(2)-O(4) bond length is 2.92 Å. In the third K site, K(3) is bonded in a 3-coordinate geometry to two equivalent P(4), one O(1), one O(2), and one O(5) atom. There is one shorter (3.40 Å) and one longer (3.79 Å) K(3)-P(4) bond length. The K(3)-O(1) bond length is 2.63 Å. The K(3)-O(2) bond length is 2.72 Å. The K(3)-O(5) bond length is 2.95 Å. In the fourth K site, K(4) is bonded in a 3-coordinate geometry to one P(4), one O(2), one O(3), and one O(4) atom. The K(4)-P(4) bond length is 3.35 Å. The K(4)-O(2) bond length is 2.87 Å. The K(4)-O(3) bond length is 2.58 Å. The K(4)-O(4) bond length is 2.82 Å. There are four inequivalent P sites. In the first P site, P(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The P(1)-O(1) bond length is 1.53 Å. The P(1)-O(2) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.53 Å. The P(1)-O(4) bond length is 1.69 Å. In the second P site, P(2) is bonded in a single-bond geometry to one P(4) and one O(5) atom. The P(2)-P(4) bond length is 2.01 Å. The P(2)-O(5) bond length is 1.54 Å. In the third P site, P(3) is bonded in a single-bond geometry to one O(4) atom. The P(3)-O(4) bond length is 1.75 Å. In the fourth P site, P(4) is bonded in a 6-coordinate geometry to one K(1), one K(2), one K(4), two equivalent K(3), and one P(2) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(3), and one P(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one K(2), one K(3), one K(4), and one P(1) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one K(1), one K(2), one K(4), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one K(1), one K(2), one K(4), one P(1), and one P(3) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(3), and one P(2) atom.