K2EuCl5 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 8-coordinate geometry to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), and two equivalent Cl(4) atoms. Eu(1) is bonded to one Cl(1), one Cl(2), one Cl(3), and four equivalent Cl(4) atoms to form distorted edge-sharing EuCl7 pentagonal bipyramids. There are four inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to four equivalent K(1) and one Eu(1) atom to form distorted ClK4Eu trigonal bipyramids that share corners with four equivalent Cl(4)K2Eu2 tetrahedra,  a cornercorner with one Cl(2)K4Eu trigonal bipyramid, corners with four equivalent Cl(1)K4Eu trigonal bipyramids, corners with four equivalent Cl(3)K4Eu trigonal bipyramids, edges with four equivalent Cl(4)K2Eu2 tetrahedra,  an edgeedge with one Cl(3)K4Eu trigonal bipyramid, edges with four equivalent Cl(2)K4Eu trigonal bipyramids, and  a faceface with one Cl(3)K4Eu trigonal bipyramid. In the second Cl site, Cl(2) is bonded to four equivalent K(1) and one Eu(1) atom to form distorted ClK4Eu trigonal bipyramids that share corners with four equivalent Cl(4)K2Eu2 tetrahedra,  a cornercorner with one Cl(1)K4Eu trigonal bipyramid, corners with four equivalent Cl(2)K4Eu trigonal bipyramids, corners with five equivalent Cl(3)K4Eu trigonal bipyramids, edges with four equivalent Cl(4)K2Eu2 tetrahedra, edges with two equivalent Cl(3)K4Eu trigonal bipyramids, and edges with four equivalent Cl(1)K4Eu trigonal bipyramids. In the third Cl site, Cl(3) is bonded to four equivalent K(1) and one Eu(1) atom to form ClK4Eu trigonal bipyramids that share corners with eight equivalent Cl(4)K2Eu2 tetrahedra, corners with four equivalent Cl(1)K4Eu trigonal bipyramids, corners with five equivalent Cl(2)K4Eu trigonal bipyramids, edges with two equivalent Cl(4)K2Eu2 tetrahedra,  an edgeedge with one Cl(1)K4Eu trigonal bipyramid, edges with two equivalent Cl(2)K4Eu trigonal bipyramids, edges with two equivalent Cl(3)K4Eu trigonal bipyramids, and  a faceface with one Cl(1)K4Eu trigonal bipyramid. In the fourth Cl site, Cl(4) is bonded to two equivalent K(1) and two equivalent Eu(1) atoms to form distorted ClK2Eu2 tetrahedra that share corners with six equivalent Cl(4)K2Eu2 tetrahedra, corners with two equivalent Cl(1)K4Eu trigonal bipyramids, corners with two equivalent Cl(2)K4Eu trigonal bipyramids, corners with four equivalent Cl(3)K4Eu trigonal bipyramids,  an edgeedge with one Cl(4)K2Eu2 tetrahedra,  an edgeedge with one Cl(3)K4Eu trigonal bipyramid, edges with two equivalent Cl(1)K4Eu trigonal bipyramids, and edges with two equivalent Cl(2)K4Eu trigonal bipyramids.
K2EuCl5 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 8-coordinate geometry to two equivalent Cl(1), two equivalent Cl(2), two equivalent Cl(3), and two equivalent Cl(4) atoms. There is one shorter (3.17 Å) and one longer (3.20 Å) K(1)-Cl(1) bond length. There is one shorter (3.25 Å) and one longer (3.35 Å) K(1)-Cl(2) bond length. There is one shorter (3.16 Å) and one longer (3.21 Å) K(1)-Cl(3) bond length. There is one shorter (3.26 Å) and one longer (3.28 Å) K(1)-Cl(4) bond length. Eu(1) is bonded to one Cl(1), one Cl(2), one Cl(3), and four equivalent Cl(4) atoms to form distorted edge-sharing EuCl7 pentagonal bipyramids. The Eu(1)-Cl(1) bond length is 2.76 Å. The Eu(1)-Cl(2) bond length is 2.74 Å. The Eu(1)-Cl(3) bond length is 2.82 Å. There are two shorter (2.80 Å) and two longer (2.83 Å) Eu(1)-Cl(4) bond lengths. There are four inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to four equivalent K(1) and one Eu(1) atom to form distorted ClK4Eu trigonal bipyramids that share corners with four equivalent Cl(4)K2Eu2 tetrahedra,  a cornercorner with one Cl(2)K4Eu trigonal bipyramid, corners with four equivalent Cl(1)K4Eu trigonal bipyramids, corners with four equivalent Cl(3)K4Eu trigonal bipyramids, edges with four equivalent Cl(4)K2Eu2 tetrahedra,  an edgeedge with one Cl(3)K4Eu trigonal bipyramid, edges with four equivalent Cl(2)K4Eu trigonal bipyramids, and  a faceface with one Cl(3)K4Eu trigonal bipyramid. In the second Cl site, Cl(2) is bonded to four equivalent K(1) and one Eu(1) atom to form distorted ClK4Eu trigonal bipyramids that share corners with four equivalent Cl(4)K2Eu2 tetrahedra,  a cornercorner with one Cl(1)K4Eu trigonal bipyramid, corners with four equivalent Cl(2)K4Eu trigonal bipyramids, corners with five equivalent Cl(3)K4Eu trigonal bipyramids, edges with four equivalent Cl(4)K2Eu2 tetrahedra, edges with two equivalent Cl(3)K4Eu trigonal bipyramids, and edges with four equivalent Cl(1)K4Eu trigonal bipyramids. In the third Cl site, Cl(3) is bonded to four equivalent K(1) and one Eu(1) atom to form ClK4Eu trigonal bipyramids that share corners with eight equivalent Cl(4)K2Eu2 tetrahedra, corners with four equivalent Cl(1)K4Eu trigonal bipyramids, corners with five equivalent Cl(2)K4Eu trigonal bipyramids, edges with two equivalent Cl(4)K2Eu2 tetrahedra,  an edgeedge with one Cl(1)K4Eu trigonal bipyramid, edges with two equivalent Cl(2)K4Eu trigonal bipyramids, edges with two equivalent Cl(3)K4Eu trigonal bipyramids, and  a faceface with one Cl(1)K4Eu trigonal bipyramid. In the fourth Cl site, Cl(4) is bonded to two equivalent K(1) and two equivalent Eu(1) atoms to form distorted ClK2Eu2 tetrahedra that share corners with six equivalent Cl(4)K2Eu2 tetrahedra, corners with two equivalent Cl(1)K4Eu trigonal bipyramids, corners with two equivalent Cl(2)K4Eu trigonal bipyramids, corners with four equivalent Cl(3)K4Eu trigonal bipyramids,  an edgeedge with one Cl(4)K2Eu2 tetrahedra,  an edgeedge with one Cl(3)K4Eu trigonal bipyramid, edges with two equivalent Cl(1)K4Eu trigonal bipyramids, and edges with two equivalent Cl(2)K4Eu trigonal bipyramids.