K3NO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. In the second K site, K(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), and four equivalent O(1) atoms. N(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(2), four equivalent K(1), and one N(1) atom. In the second O site, O(2) is bonded to one K(2), four equivalent K(1), and one N(1) atom to form distorted corner-sharing OK5N octahedra. The corner-sharing octahedral tilt angles are 51°. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(2), four equivalent K(1), and one N(1) atom.
K3NO4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Both K(1)-O(2) bond lengths are 2.71 Å. There is one shorter (2.71 Å) and one longer (2.76 Å) K(1)-O(3) bond length. There are a spread of K(1)-O(1) bond distances ranging from 2.81-3.15 Å. In the second K site, K(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), and four equivalent O(1) atoms. The K(2)-O(2) bond length is 2.54 Å. The K(2)-O(3) bond length is 2.59 Å. There are two shorter (2.72 Å) and two longer (2.85 Å) K(2)-O(1) bond lengths. N(1) is bonded in a tetrahedral geometry to one O(2), one O(3), and two equivalent O(1) atoms. The N(1)-O(2) bond length is 1.39 Å. The N(1)-O(3) bond length is 1.40 Å. Both N(1)-O(1) bond lengths are 1.39 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(2), four equivalent K(1), and one N(1) atom. In the second O site, O(2) is bonded to one K(2), four equivalent K(1), and one N(1) atom to form distorted corner-sharing OK5N octahedra. The corner-sharing octahedral tilt angles are 51°. In the third O site, O(3) is bonded in a 6-coordinate geometry to one K(2), four equivalent K(1), and one N(1) atom.