K2PdO4 crystallizes in the monoclinic P2_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(1), and three equivalent O(2) atoms. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(4), and three equivalent O(3) atoms. Pd(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Pd(1) atom. In the second O site, O(2) is bonded to one K(2), three equivalent K(1), and one Pd(1) atom to form distorted corner-sharing OK4Pd trigonal bipyramids. In the third O site, O(3) is bonded in a 5-coordinate geometry to one K(1), three equivalent K(2), and one Pd(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), two equivalent K(2), and one Pd(1) atom.
K2PdO4 crystallizes in the monoclinic P2_1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one O(3), one O(4), two equivalent O(1), and three equivalent O(2) atoms. The K(1)-O(3) bond length is 2.83 Å. The K(1)-O(4) bond length is 2.98 Å. There is one shorter (2.76 Å) and one longer (2.88 Å) K(1)-O(1) bond length. There is one shorter (2.86 Å) and two longer (2.88 Å) K(1)-O(2) bond lengths. In the second K site, K(2) is bonded in a 8-coordinate geometry to one O(2), two equivalent O(1), two equivalent O(4), and three equivalent O(3) atoms. The K(2)-O(2) bond length is 2.85 Å. There is one shorter (3.08 Å) and one longer (3.23 Å) K(2)-O(1) bond length. There is one shorter (2.91 Å) and one longer (2.93 Å) K(2)-O(4) bond length. There are a spread of K(2)-O(3) bond distances ranging from 2.73-3.03 Å. Pd(1) is bonded in a rectangular see-saw-like geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Pd(1)-O(1) bond length is 1.88 Å. The Pd(1)-O(2) bond length is 1.92 Å. The Pd(1)-O(3) bond length is 1.89 Å. The Pd(1)-O(4) bond length is 1.92 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one Pd(1) atom. In the second O site, O(2) is bonded to one K(2), three equivalent K(1), and one Pd(1) atom to form distorted corner-sharing OK4Pd trigonal bipyramids. In the third O site, O(3) is bonded in a 5-coordinate geometry to one K(1), three equivalent K(2), and one Pd(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(1), two equivalent K(2), and one Pd(1) atom.