K2B(PO4)2 crystallizes in the tetragonal I-42d space group. K(1) is bonded in a 8-coordinate geometry to two equivalent O(2) and six equivalent O(1) atoms. B(1) is bonded to four equivalent O(2) atoms to form BO4 tetrahedra that share corners with four equivalent P(1)O4 tetrahedra. P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with two equivalent B(1)O4 tetrahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent K(1) and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(1), one B(1), and one P(1) atom.
K2B(PO4)2 crystallizes in the tetragonal I-42d space group. K(1) is bonded in a 8-coordinate geometry to two equivalent O(2) and six equivalent O(1) atoms. Both K(1)-O(2) bond lengths are 2.99 Å. There are a spread of K(1)-O(1) bond distances ranging from 2.79-3.00 Å. B(1) is bonded to four equivalent O(2) atoms to form BO4 tetrahedra that share corners with four equivalent P(1)O4 tetrahedra. All B(1)-O(2) bond lengths are 1.47 Å. P(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with two equivalent B(1)O4 tetrahedra. Both P(1)-O(1) bond lengths are 1.52 Å. Both P(1)-O(2) bond lengths are 1.58 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent K(1) and one P(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one K(1), one B(1), and one P(1) atom.