K2FeP2O7 crystallizes in the tetragonal P-42_1m space group. K(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. Fe(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form corner-sharing PO4 tetrahedra. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1) and two equivalent P(1) atoms. In the second O site, O(2) is bonded in a distorted single-bond geometry to three equivalent K(1) and one P(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(1) atom.
K2FeP2O7 crystallizes in the tetragonal P-42_1m space group. K(1) is bonded in a 8-coordinate geometry to one O(1), three equivalent O(2), and four equivalent O(3) atoms. The K(1)-O(1) bond length is 2.85 Å. There are two shorter (2.71 Å) and one longer (2.83 Å) K(1)-O(2) bond length. There are two shorter (3.14 Å) and two longer (3.20 Å) K(1)-O(3) bond lengths. Fe(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. All Fe(1)-O(3) bond lengths are 2.01 Å. P(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form corner-sharing PO4 tetrahedra. The P(1)-O(1) bond length is 1.65 Å. The P(1)-O(2) bond length is 1.52 Å. Both P(1)-O(3) bond lengths are 1.53 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1) and two equivalent P(1) atoms. In the second O site, O(2) is bonded in a distorted single-bond geometry to three equivalent K(1) and one P(1) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent K(1), one Fe(1), and one P(1) atom.