KBaAsSe3 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one As(1), one Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms. As(1) is bonded in a 3-coordinate geometry to one K(1), one Se(1), one Se(2), and one Se(3) atom. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent K(1), two equivalent Ba(1), and one As(1) atom. In the second Se site, Se(2) is bonded to one K(1), four equivalent Ba(1), and one As(1) atom to form a mixture of distorted corner and edge-sharing SeKBa4As octahedra. The corner-sharing octahedral tilt angles range from 25-36°. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to three equivalent K(1), two equivalent Ba(1), and one As(1) atom.
KBaAsSe3 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 8-coordinate geometry to one As(1), one Se(2), three equivalent Se(1), and three equivalent Se(3) atoms. The K(1)-As(1) bond length is 3.78 Å. The K(1)-Se(2) bond length is 3.62 Å. There are a spread of K(1)-Se(1) bond distances ranging from 3.40-3.86 Å. There are a spread of K(1)-Se(3) bond distances ranging from 3.33-3.89 Å. Ba(1) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms. There is one shorter (3.32 Å) and one longer (3.66 Å) Ba(1)-Se(1) bond length. There is one shorter (3.39 Å) and one longer (3.42 Å) Ba(1)-Se(3) bond length. There are a spread of Ba(1)-Se(2) bond distances ranging from 3.36-3.52 Å. As(1) is bonded in a 3-coordinate geometry to one K(1), one Se(1), one Se(2), and one Se(3) atom. The As(1)-Se(1) bond length is 2.41 Å. The As(1)-Se(2) bond length is 2.48 Å. The As(1)-Se(3) bond length is 2.41 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent K(1), two equivalent Ba(1), and one As(1) atom. In the second Se site, Se(2) is bonded to one K(1), four equivalent Ba(1), and one As(1) atom to form a mixture of distorted corner and edge-sharing SeKBa4As octahedra. The corner-sharing octahedral tilt angles range from 25-36°. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to three equivalent K(1), two equivalent Ba(1), and one As(1) atom.