KMnPO4 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(8) atoms. In the second K site, K(2) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and one O(7) atom. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form MnO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(8), and two equivalent O(4) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O4 tetrahedra. In the second P site, P(2) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Mn(1), and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one Mn(2), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(2), one Mn(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(2), two equivalent Mn(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one K(2), one Mn(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent K(1), one Mn(2), and one P(2) atom.
KMnPO4 crystallizes in the triclinic P-1 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), two equivalent O(1), two equivalent O(2), and two equivalent O(8) atoms. The K(1)-O(5) bond length is 3.30 Å. The K(1)-O(6) bond length is 3.12 Å. There is one shorter (3.03 Å) and one longer (3.20 Å) K(1)-O(1) bond length. There is one shorter (2.77 Å) and one longer (2.91 Å) K(1)-O(2) bond length. There is one shorter (2.71 Å) and one longer (2.90 Å) K(1)-O(8) bond length. In the second K site, K(2) is bonded in a 5-coordinate geometry to one O(3), one O(4), one O(5), one O(6), and one O(7) atom. The K(2)-O(3) bond length is 2.83 Å. The K(2)-O(4) bond length is 2.72 Å. The K(2)-O(5) bond length is 2.80 Å. The K(2)-O(6) bond length is 2.86 Å. The K(2)-O(7) bond length is 2.75 Å. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form MnO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. The Mn(1)-O(1) bond length is 2.05 Å. The Mn(1)-O(5) bond length is 2.07 Å. The Mn(1)-O(6) bond length is 2.07 Å. The Mn(1)-O(7) bond length is 2.07 Å. In the second Mn site, Mn(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(8), and two equivalent O(4) atoms. The Mn(2)-O(2) bond length is 2.09 Å. The Mn(2)-O(3) bond length is 2.08 Å. The Mn(2)-O(8) bond length is 2.12 Å. There is one shorter (2.10 Å) and one longer (2.56 Å) Mn(2)-O(4) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(1), one O(3), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mn(1)O4 tetrahedra. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.56 Å. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(6) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(2), one O(4), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Mn(1)O4 tetrahedra. The P(2)-O(2) bond length is 1.55 Å. The P(2)-O(4) bond length is 1.57 Å. The P(2)-O(7) bond length is 1.55 Å. The P(2)-O(8) bond length is 1.56 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Mn(1), and one P(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent K(1), one Mn(2), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one K(2), one Mn(2), and one P(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one K(2), two equivalent Mn(2), and one P(2) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one K(1), one K(2), one Mn(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one K(2), one Mn(1), and one P(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to two equivalent K(1), one Mn(2), and one P(2) atom.