RbNdF4 crystallizes in the orthorhombic Pnma space group. Rb(1) is bonded in a 7-coordinate geometry to one F(3), two equivalent F(1), and four equivalent F(4) atoms. Nd(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 Rb(1) and two equivalent Nd(1) atoms to form distorted FRb2Nd2 tetrahedra that share corners with four equivalent F(1)Rb2Nd2 tetrahedra, corners with six equivalent F(3)RbNd3 tetrahedra, and  an edgeedge with one F(3)RbNd3 tetrahedra. In the second F site, F(2) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Nd(1) atoms. In the third F site, F(3) is bonded to one Rb(1) and three equivalent Nd(1) atoms to form FRbNd3 tetrahedra that share corners with two equivalent F(3)RbNd3 tetrahedra, corners with six equivalent F(1)Rb2Nd2 tetrahedra,  an edgeedge with one F(1)Rb2Nd2 tetrahedra, and edges with two equivalent F(3)RbNd3 tetrahedra. In the fourth F site, F(4) is bonded in a 5-coordinate geometry to four equivalent Rb(1) and one Nd(1) atom.
RbNdF4 crystallizes in the orthorhombic Pnma space group. Rb(1) is bonded in a 7-coordinate geometry to one F(3), two equivalent F(1), and four equivalent F(4) atoms. The Rb(1)-F(3) bond length is 2.74 Å. There is one shorter (2.71 Å) and one longer (2.83 Å) Rb(1)-F(1) bond length. There are two shorter (2.79 Å) and two longer (2.84 Å) Rb(1)-F(4) bond lengths. Nd(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 Nd(1)-F(4) bond length is 2.30 Å. Both Nd(1)-F(1) bond lengths are 2.37 Å. There is one shorter (2.45 Å) and two longer (2.52 Å) Nd(1)-F(2) bond lengths. There is one shorter (2.41 Å) and two longer (2.47 Å) Nd(1)-F(3) bond lengths. There are four inequivalent F sites. In the first F site, F(1) is bonded to two equivalent Rb(1) and two equivalent Nd(1) atoms to form distorted FRb2Nd2 tetrahedra that share corners with four equivalent F(1)Rb2Nd2 tetrahedra, corners with six equivalent F(3)RbNd3 tetrahedra, and  an edgeedge with one F(3)RbNd3 tetrahedra. In the second F site, F(2) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Nd(1) atoms. In the third F site, F(3) is bonded to one Rb(1) and three equivalent Nd(1) atoms to form FRbNd3 tetrahedra that share corners with two equivalent F(3)RbNd3 tetrahedra, corners with six equivalent F(1)Rb2Nd2 tetrahedra,  an edgeedge with one F(1)Rb2Nd2 tetrahedra, and edges with two equivalent F(3)RbNd3 tetrahedra. In the fourth F site, F(4) is bonded in a 5-coordinate geometry to four equivalent Rb(1) and one Nd(1) atom.