KCo2(PO4)2 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(1) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(6), one O(7), and one O(8) atom to form CoO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. In the second Co site, Co(2) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form CoO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra and corners with three equivalent Co(2)O4 tetrahedra. In the second P site, P(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O4 tetrahedra and corners with three equivalent Co(1)O4 tetrahedra. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a distorted bent 150 degrees geometry to one K(1), one Co(1), and one P(2) atom. In the second O site, O(8) is bonded in a 2-coordinate geometry to one K(1), one Co(1), and one P(2) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Co(2), and one P(2) atom. In the fourth O site, O(2) is bonded in a bent 120 degrees geometry to one K(1), one Co(1), and one P(2) atom. In the fifth O site, O(6) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one K(1), one Co(2), and one P(1) atom. In the seventh O site, O(4) is bonded in a 2-coordinate geometry to one K(1), one Co(2), and one P(1) atom. In the eighth O site, O(5) is bonded in a 2-coordinate geometry to one K(1), one Co(2), and one P(1) atom.
KCo2(PO4)2 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 9-coordinate geometry to one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), one O(8), and two equivalent O(1) atoms. The K(1)-O(2) bond length is 3.31 Å. The K(1)-O(3) bond length is 3.21 Å. The K(1)-O(4) bond length is 3.06 Å. The K(1)-O(5) bond length is 3.15 Å. The K(1)-O(6) bond length is 2.79 Å. The K(1)-O(7) bond length is 3.05 Å. The K(1)-O(8) bond length is 3.05 Å. There is one shorter (2.93 Å) and one longer (3.11 Å) K(1)-O(1) bond length. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(6), one O(7), and one O(8) atom to form CoO4 tetrahedra that share  a cornercorner with one P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Co(1)-O(2) bond length is 1.93 Å. The Co(1)-O(6) bond length is 1.91 Å. The Co(1)-O(7) bond length is 1.88 Å. The Co(1)-O(8) bond length is 1.89 Å. In the second Co site, Co(2) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form CoO4 tetrahedra that share  a cornercorner with one P(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. The Co(2)-O(1) bond length is 1.93 Å. The Co(2)-O(3) bond length is 1.90 Å. The Co(2)-O(4) bond length is 1.92 Å. The Co(2)-O(5) bond length is 1.89 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share  a cornercorner with one Co(1)O4 tetrahedra and corners with three equivalent Co(2)O4 tetrahedra. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.55 Å. The P(1)-O(5) bond length is 1.55 Å. The P(1)-O(6) bond length is 1.56 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Co(2)O4 tetrahedra and corners with three equivalent Co(1)O4 tetrahedra. The P(2)-O(1) bond length is 1.54 Å. The P(2)-O(2) bond length is 1.55 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(7) is bonded in a distorted bent 150 degrees geometry to one K(1), one Co(1), and one P(2) atom. In the second O site, O(8) is bonded in a 2-coordinate geometry to one K(1), one Co(1), and one P(2) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to two equivalent K(1), one Co(2), and one P(2) atom. In the fourth O site, O(2) is bonded in a bent 120 degrees geometry to one K(1), one Co(1), and one P(2) atom. In the fifth O site, O(6) is bonded in a 3-coordinate geometry to one K(1), one Co(1), and one P(1) atom. In the sixth O site, O(3) is bonded in a distorted bent 150 degrees geometry to one K(1), one Co(2), and one P(1) atom. In the seventh O site, O(4) is bonded in a 2-coordinate geometry to one K(1), one Co(2), and one P(1) atom. In the eighth O site, O(5) is bonded in a 2-coordinate geometry to one K(1), one Co(2), and one P(1) atom.