K2FeO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to two equivalent O(2), three equivalent O(3), and four equivalent O(1) atoms. In the second K site, K(2) is bonded in a 10-coordinate geometry to one O(3), three equivalent O(2), and six equivalent O(1) atoms. Fe(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1), three equivalent K(2), and one Fe(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1), three equivalent K(2), and one Fe(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), three equivalent K(1), and one Fe(1) atom.
K2FeO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 9-coordinate geometry to two equivalent O(2), three equivalent O(3), and four equivalent O(1) atoms. There is one shorter (2.71 Å) and one longer (2.75 Å) K(1)-O(2) bond length. There is one shorter (2.88 Å) and two longer (3.11 Å) K(1)-O(3) bond lengths. There are two shorter (2.71 Å) and two longer (2.77 Å) K(1)-O(1) bond lengths. In the second K site, K(2) is bonded in a 10-coordinate geometry to one O(3), three equivalent O(2), and six equivalent O(1) atoms. The K(2)-O(3) bond length is 2.72 Å. There are two shorter (2.91 Å) and one longer (3.21 Å) K(2)-O(2) bond length. There are a spread of K(2)-O(1) bond distances ranging from 2.91-3.20 Å. Fe(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. The Fe(1)-O(2) bond length is 1.65 Å. The Fe(1)-O(3) bond length is 1.64 Å. Both Fe(1)-O(1) bond lengths are 1.64 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(1), three equivalent K(2), and one Fe(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent K(1), three equivalent K(2), and one Fe(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one K(2), three equivalent K(1), and one Fe(1) atom.