KLaF4 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 7-coordinate geometry to one F(3), two equivalent F(1), and four equivalent F(4) atoms. La(1) is bonded in a 9-coordinate geometry to one F(4), two equivalent F(1), three equivalent F(2), and three equivalent F(3) atoms. There are four inequivalent F sites. In the first F site, F(1) is bonded to two equivalent K(1) and two equivalent La(1) atoms to form FK2La2 tetrahedra that share corners with four equivalent F(1)K2La2 tetrahedra, corners with six equivalent F(3)KLa3 tetrahedra, and  an edgeedge with one F(3)KLa3 tetrahedra. In the second F site, F(2) is bonded in a trigonal non-coplanar geometry to three equivalent La(1) atoms. In the third F site, F(3) is bonded to one K(1) and three equivalent La(1) atoms to form FKLa3 tetrahedra that share corners with two equivalent F(3)KLa3 tetrahedra, corners with six equivalent F(1)K2La2 tetrahedra,  an edgeedge with one F(1)K2La2 tetrahedra, and edges with two equivalent F(3)KLa3 tetrahedra. In the fourth F site, F(4) is bonded in a 5-coordinate geometry to four equivalent K(1) and one La(1) atom.
KLaF4 crystallizes in the orthorhombic Pnma space group. K(1) is bonded in a 7-coordinate geometry to one F(3), two equivalent F(1), and four equivalent F(4) atoms. The K(1)-F(3) bond length is 2.60 Å. There is one shorter (2.60 Å) and one longer (2.62 Å) K(1)-F(1) bond length. There are two shorter (2.73 Å) and two longer (2.76 Å) K(1)-F(4) bond lengths. La(1) is bonded in a 9-coordinate geometry to one F(4), two equivalent F(1), three equivalent F(2), and three equivalent F(3) atoms. The La(1)-F(4) bond length is 2.34 Å. Both La(1)-F(1) bond lengths are 2.42 Å. There is one shorter (2.47 Å) and two longer (2.56 Å) La(1)-F(2) bond lengths. There is one shorter (2.46 Å) and two longer (2.51 Å) La(1)-F(3) bond lengths. There are four inequivalent F sites. In the first F site, F(1) is bonded to two equivalent K(1) and two equivalent La(1) atoms to form FK2La2 tetrahedra that share corners with four equivalent F(1)K2La2 tetrahedra, corners with six equivalent F(3)KLa3 tetrahedra, and  an edgeedge with one F(3)KLa3 tetrahedra. In the second F site, F(2) is bonded in a trigonal non-coplanar geometry to three equivalent La(1) atoms. In the third F site, F(3) is bonded to one K(1) and three equivalent La(1) atoms to form FKLa3 tetrahedra that share corners with two equivalent F(3)KLa3 tetrahedra, corners with six equivalent F(1)K2La2 tetrahedra,  an edgeedge with one F(1)K2La2 tetrahedra, and edges with two equivalent F(3)KLa3 tetrahedra. In the fourth F site, F(4) is bonded in a 5-coordinate geometry to four equivalent K(1) and one La(1) atom.