KBa(Fe2Se3)2 crystallizes in the orthorhombic Pmc2_1 space group. K(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(3), two equivalent Se(2), two equivalent Se(4), and two equivalent Se(6) atoms. Ba(1) is bonded in a 9-coordinate geometry to one Se(4), two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(5) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Se(2), one Se(3), one Se(5), and one Se(6) atom to form a mixture of distorted edge and corner-sharing FeSe4 tetrahedra. In the second Fe site, Fe(2) is bonded to one Se(1), one Se(4), one Se(5), and one Se(6) atom to form a mixture of distorted edge and corner-sharing FeSe4 tetrahedra. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to one K(1), two equivalent Ba(1), and two equivalent Fe(2) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Ba(1), and two equivalent Fe(1) atoms. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), two equivalent Ba(1), and two equivalent Fe(1) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to two equivalent K(1), one Ba(1), and two equivalent Fe(2) atoms. In the fifth Se site, Se(5) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and two equivalent Fe(2) atoms. In the sixth Se site, Se(6) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Fe(1), and two equivalent Fe(2) atoms.
KBa(Fe2Se3)2 crystallizes in the orthorhombic Pmc2_1 space group. K(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(3), two equivalent Se(2), two equivalent Se(4), and two equivalent Se(6) atoms. The K(1)-Se(1) bond length is 3.80 Å. The K(1)-Se(3) bond length is 3.57 Å. Both K(1)-Se(2) bond lengths are 3.43 Å. Both K(1)-Se(4) bond lengths are 3.48 Å. Both K(1)-Se(6) bond lengths are 3.64 Å. Ba(1) is bonded in a 9-coordinate geometry to one Se(4), two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(5) atoms. The Ba(1)-Se(4) bond length is 3.53 Å. Both Ba(1)-Se(1) bond lengths are 3.43 Å. There is one shorter (3.72 Å) and one longer (3.98 Å) Ba(1)-Se(2) bond length. Both Ba(1)-Se(3) bond lengths are 3.44 Å. Both Ba(1)-Se(5) bond lengths are 3.64 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one Se(2), one Se(3), one Se(5), and one Se(6) atom to form a mixture of distorted edge and corner-sharing FeSe4 tetrahedra. The Fe(1)-Se(2) bond length is 2.38 Å. The Fe(1)-Se(3) bond length is 2.41 Å. The Fe(1)-Se(5) bond length is 2.46 Å. The Fe(1)-Se(6) bond length is 2.44 Å. In the second Fe site, Fe(2) is bonded to one Se(1), one Se(4), one Se(5), and one Se(6) atom to form a mixture of distorted edge and corner-sharing FeSe4 tetrahedra. The Fe(2)-Se(1) bond length is 2.41 Å. The Fe(2)-Se(4) bond length is 2.37 Å. The Fe(2)-Se(5) bond length is 2.45 Å. The Fe(2)-Se(6) bond length is 2.45 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to one K(1), two equivalent Ba(1), and two equivalent Fe(2) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Ba(1), and two equivalent Fe(1) atoms. In the third Se site, Se(3) is bonded in a 5-coordinate geometry to one K(1), two equivalent Ba(1), and two equivalent Fe(1) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to two equivalent K(1), one Ba(1), and two equivalent Fe(2) atoms. In the fifth Se site, Se(5) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Fe(1), and two equivalent Fe(2) atoms. In the sixth Se site, Se(6) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Fe(1), and two equivalent Fe(2) atoms.