KSn2(PO4)3 crystallizes in the trigonal R-3 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent O(4) atoms to form distorted KO6 cuboctahedra that share corners with six equivalent P(1)O4 tetrahedra and faces with two equivalent Sn(2)O6 octahedra. In the second K site, K(2) is bonded in a distorted hexagonal planar geometry to six equivalent O(1) atoms. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form SnO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. In the second Sn site, Sn(2) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form SnO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra and  a faceface with one K(1)O6 cuboctahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one K(1)O6 cuboctahedra, corners with two equivalent Sn(1)O6 octahedra, and corners with two equivalent Sn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-44°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one K(2), one Sn(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sn(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Sn(2), and one P(1) atom.
KSn2(PO4)3 crystallizes in the trigonal R-3 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent O(4) atoms to form distorted KO6 cuboctahedra that share corners with six equivalent P(1)O4 tetrahedra and faces with two equivalent Sn(2)O6 octahedra. All K(1)-O(4) bond lengths are 2.74 Å. In the second K site, K(2) is bonded in a distorted hexagonal planar geometry to six equivalent O(1) atoms. All K(2)-O(1) bond lengths are 2.89 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form SnO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra. All Sn(1)-O(1) bond lengths are 2.07 Å. All Sn(1)-O(2) bond lengths are 2.06 Å. In the second Sn site, Sn(2) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form SnO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra and  a faceface with one K(1)O6 cuboctahedra. All Sn(2)-O(3) bond lengths are 2.05 Å. All Sn(2)-O(4) bond lengths are 2.07 Å. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share  a cornercorner with one K(1)O6 cuboctahedra, corners with two equivalent Sn(1)O6 octahedra, and corners with two equivalent Sn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 29-44°. The P(1)-O(1) bond length is 1.55 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.55 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one K(2), one Sn(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Sn(1) and one P(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Sn(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one K(1), one Sn(2), and one P(1) atom.