K2Sn2Se5 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), three equivalent Se(2), and three equivalent Se(3) atoms. Sn(1) is bonded to one Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form a mixture of corner and edge-sharing SnSe5 trigonal bipyramids. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to four equivalent K(1) and two equivalent Sn(1) atoms. In the second Se site, Se(2) is bonded to three equivalent K(1) and two equivalent Sn(1) atoms to form a mixture of corner and edge-sharing SeK3Sn2 square pyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to three equivalent K(1) and two equivalent Sn(1) atoms.
K2Sn2Se5 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), three equivalent Se(2), and three equivalent Se(3) atoms. There is one shorter (3.72 Å) and one longer (3.84 Å) K(1)-Se(1) bond length. There are a spread of K(1)-Se(2) bond distances ranging from 3.31-3.54 Å. There are a spread of K(1)-Se(3) bond distances ranging from 3.28-3.75 Å. Sn(1) is bonded to one Se(1), two equivalent Se(2), and two equivalent Se(3) atoms to form a mixture of corner and edge-sharing SnSe5 trigonal bipyramids. The Sn(1)-Se(1) bond length is 2.63 Å. There is one shorter (2.54 Å) and one longer (2.83 Å) Sn(1)-Se(2) bond length. There is one shorter (2.58 Å) and one longer (2.71 Å) Sn(1)-Se(3) bond length. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to four equivalent K(1) and two equivalent Sn(1) atoms. In the second Se site, Se(2) is bonded to three equivalent K(1) and two equivalent Sn(1) atoms to form a mixture of corner and edge-sharing SeK3Sn2 square pyramids. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to three equivalent K(1) and two equivalent Sn(1) atoms.