Na4Sn3F10 crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one F(1), one F(5), two equivalent F(2), and two equivalent F(4) atoms to form a mixture of distorted edge and corner-sharing NaF6 octahedra. The corner-sharing octahedral tilt angles are 64°. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent F(1), two equivalent F(3), and two equivalent F(5) atoms. In the third Na site, Na(3) is bonded to two equivalent F(5) and four equivalent F(3) atoms to form a mixture of edge and corner-sharing NaF6 octahedra. The corner-sharing octahedral tilt angles are 64°. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a distorted rectangular see-saw-like geometry to one F(2), one F(3), one F(4), and one F(5) atom. In the second Sn site, Sn(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent F(1) and two equivalent F(4) atoms. There are five inequivalent F sites. In the first F site, F(2) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Sn(1) atom. In the second F site, F(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(3), and one Sn(1) atom. In the third F site, F(4) is bonded to two equivalent Na(1), one Sn(1), and one Sn(2) atom to form distorted FNa2Sn2 tetrahedra that share  a cornercorner with one F(4)Na2Sn2 tetrahedra,  a cornercorner with one F(5)Na3Sn tetrahedra,  an edgeedge with one F(4)Na2Sn2 tetrahedra, and  an edgeedge with one F(5)Na3Sn tetrahedra. In the fourth F site, F(5) is bonded to one Na(1), one Na(2), one Na(3), and one Sn(1) atom to form FNa3Sn tetrahedra that share  a cornercorner with one F(4)Na2Sn2 tetrahedra, corners with two equivalent F(5)Na3Sn tetrahedra, and  an edgeedge with one F(4)Na2Sn2 tetrahedra. In the fifth F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one Na(2), and one Sn(2) atom.
Na4Sn3F10 crystallizes in the monoclinic C2/c space group. There are three inequivalent Na sites. In the first Na site, Na(1) is bonded to one F(1), one F(5), two equivalent F(2), and two equivalent F(4) atoms to form a mixture of distorted edge and corner-sharing NaF6 octahedra. The corner-sharing octahedral tilt angles are 64°. The Na(1)-F(1) bond length is 2.25 Å. The Na(1)-F(5) bond length is 2.27 Å. There is one shorter (2.26 Å) and one longer (2.29 Å) Na(1)-F(2) bond length. There is one shorter (2.34 Å) and one longer (2.35 Å) Na(1)-F(4) bond length. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to two equivalent F(1), two equivalent F(3), and two equivalent F(5) atoms. Both Na(2)-F(1) bond lengths are 2.29 Å. Both Na(2)-F(3) bond lengths are 2.43 Å. Both Na(2)-F(5) bond lengths are 2.23 Å. In the third Na site, Na(3) is bonded to two equivalent F(5) and four equivalent F(3) atoms to form a mixture of edge and corner-sharing NaF6 octahedra. The corner-sharing octahedral tilt angles are 64°. Both Na(3)-F(5) bond lengths are 2.26 Å. There are two shorter (2.26 Å) and two longer (2.28 Å) Na(3)-F(3) bond lengths. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a distorted rectangular see-saw-like geometry to one F(2), one F(3), one F(4), and one F(5) atom. The Sn(1)-F(2) bond length is 2.04 Å. The Sn(1)-F(3) bond length is 2.16 Å. The Sn(1)-F(4) bond length is 2.38 Å. The Sn(1)-F(5) bond length is 2.09 Å. In the second Sn site, Sn(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent F(1) and two equivalent F(4) atoms. Both Sn(2)-F(1) bond lengths are 2.04 Å. Both Sn(2)-F(4) bond lengths are 2.28 Å. There are five inequivalent F sites. In the first F site, F(2) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Sn(1) atom. In the second F site, F(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(3), and one Sn(1) atom. In the third F site, F(4) is bonded to two equivalent Na(1), one Sn(1), and one Sn(2) atom to form distorted FNa2Sn2 tetrahedra that share  a cornercorner with one F(4)Na2Sn2 tetrahedra,  a cornercorner with one F(5)Na3Sn tetrahedra,  an edgeedge with one F(4)Na2Sn2 tetrahedra, and  an edgeedge with one F(5)Na3Sn tetrahedra. In the fourth F site, F(5) is bonded to one Na(1), one Na(2), one Na(3), and one Sn(1) atom to form FNa3Sn tetrahedra that share  a cornercorner with one F(4)Na2Sn2 tetrahedra, corners with two equivalent F(5)Na3Sn tetrahedra, and  an edgeedge with one F(4)Na2Sn2 tetrahedra. In the fifth F site, F(1) is bonded in a distorted trigonal non-coplanar geometry to one Na(1), one Na(2), and one Sn(2) atom.