K2YbF5 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 8-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(3), and two equivalent F(4) atoms. Yb(1) is bonded to one F(1), one F(2), one F(3), and four equivalent F(4) atoms to form distorted edge-sharing YbF7 pentagonal bipyramids. There are four inequivalent F sites. In the first F site, F(1) is bonded to four equivalent K(1) and one Yb(1) atom to form distorted FK4Yb trigonal bipyramids that share corners with four equivalent F(4)K2Yb2 tetrahedra, corners with four equivalent F(1)K4Yb trigonal bipyramids, corners with four equivalent F(3)K4Yb trigonal bipyramids, edges with four equivalent F(4)K2Yb2 tetrahedra,  an edgeedge with one F(3)K4Yb trigonal bipyramid, and  a faceface with one F(3)K4Yb trigonal bipyramid. In the second F site, F(2) is bonded in a 5-coordinate geometry to four equivalent K(1) and one Yb(1) atom. In the third F site, F(3) is bonded to four equivalent K(1) and one Yb(1) atom to form distorted FK4Yb trigonal bipyramids that share corners with eight equivalent F(4)K2Yb2 tetrahedra, corners with four equivalent F(1)K4Yb trigonal bipyramids, edges with two equivalent F(4)K2Yb2 tetrahedra,  an edgeedge with one F(1)K4Yb trigonal bipyramid, edges with two equivalent F(3)K4Yb trigonal bipyramids, and  a faceface with one F(1)K4Yb trigonal bipyramid. In the fourth F site, F(4) is bonded to two equivalent K(1) and two equivalent Yb(1) atoms to form distorted FK2Yb2 tetrahedra that share corners with six equivalent F(4)K2Yb2 tetrahedra, corners with two equivalent F(1)K4Yb trigonal bipyramids, corners with four equivalent F(3)K4Yb trigonal bipyramids,  an edgeedge with one F(4)K2Yb2 tetrahedra,  an edgeedge with one F(3)K4Yb trigonal bipyramid, and edges with two equivalent F(1)K4Yb trigonal bipyramids.
K2YbF5 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 8-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(3), and two equivalent F(4) atoms. There is one shorter (2.69 Å) and one longer (2.73 Å) K(1)-F(1) bond length. There is one shorter (2.79 Å) and one longer (2.82 Å) K(1)-F(2) bond length. Both K(1)-F(3) bond lengths are 2.72 Å. There is one shorter (2.76 Å) and one longer (2.77 Å) K(1)-F(4) bond length. Yb(1) is bonded to one F(1), one F(2), one F(3), and four equivalent F(4) atoms to form distorted edge-sharing YbF7 pentagonal bipyramids. The Yb(1)-F(1) bond length is 2.28 Å. The Yb(1)-F(2) bond length is 2.25 Å. The Yb(1)-F(3) bond length is 2.30 Å. There are two shorter (2.28 Å) and two longer (2.31 Å) Yb(1)-F(4) bond lengths. There are four inequivalent F sites. In the first F site, F(1) is bonded to four equivalent K(1) and one Yb(1) atom to form distorted FK4Yb trigonal bipyramids that share corners with four equivalent F(4)K2Yb2 tetrahedra, corners with four equivalent F(1)K4Yb trigonal bipyramids, corners with four equivalent F(3)K4Yb trigonal bipyramids, edges with four equivalent F(4)K2Yb2 tetrahedra,  an edgeedge with one F(3)K4Yb trigonal bipyramid, and  a faceface with one F(3)K4Yb trigonal bipyramid. In the second F site, F(2) is bonded in a 5-coordinate geometry to four equivalent K(1) and one Yb(1) atom. In the third F site, F(3) is bonded to four equivalent K(1) and one Yb(1) atom to form distorted FK4Yb trigonal bipyramids that share corners with eight equivalent F(4)K2Yb2 tetrahedra, corners with four equivalent F(1)K4Yb trigonal bipyramids, edges with two equivalent F(4)K2Yb2 tetrahedra,  an edgeedge with one F(1)K4Yb trigonal bipyramid, edges with two equivalent F(3)K4Yb trigonal bipyramids, and  a faceface with one F(1)K4Yb trigonal bipyramid. In the fourth F site, F(4) is bonded to two equivalent K(1) and two equivalent Yb(1) atoms to form distorted FK2Yb2 tetrahedra that share corners with six equivalent F(4)K2Yb2 tetrahedra, corners with two equivalent F(1)K4Yb trigonal bipyramids, corners with four equivalent F(3)K4Yb trigonal bipyramids,  an edgeedge with one F(4)K2Yb2 tetrahedra,  an edgeedge with one F(3)K4Yb trigonal bipyramid, and edges with two equivalent F(1)K4Yb trigonal bipyramids.