Na3HfF7 crystallizes in the monoclinic Cm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one F(1), one F(4), one F(5), two equivalent F(2), and two equivalent F(3) atoms. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one F(1), one F(4), one F(5), and two equivalent F(2) atoms. Hf(1) is bonded in a distorted pentagonal bipyramidal geometry to one F(1), one F(4), one F(5), two equivalent F(2), and two equivalent F(3) atoms. There are five inequivalent F sites. In the first F site, F(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(1), and one Hf(1) atom. In the second F site, F(2) is bonded to one Na(2), two equivalent Na(1), and one Hf(1) atom to form a mixture of corner and edge-sharing FNa3Hf tetrahedra. In the third F site, F(3) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Hf(1) atom. In the fourth F site, F(4) is bonded to one Na(2), two equivalent Na(1), and one Hf(1) atom to form a mixture of corner and edge-sharing FNa3Hf tetrahedra. In the fifth F site, F(5) is bonded to one Na(2), two equivalent Na(1), and one Hf(1) atom to form a mixture of corner and edge-sharing FNa3Hf tetrahedra.
Na3HfF7 crystallizes in the monoclinic Cm space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 7-coordinate geometry to one F(1), one F(4), one F(5), two equivalent F(2), and two equivalent F(3) atoms. The Na(1)-F(1) bond length is 2.47 Å. The Na(1)-F(4) bond length is 2.30 Å. The Na(1)-F(5) bond length is 2.33 Å. Both Na(1)-F(2) bond lengths are 2.31 Å. There is one shorter (2.31 Å) and one longer (2.45 Å) Na(1)-F(3) bond length. In the second Na site, Na(2) is bonded in a 5-coordinate geometry to one F(1), one F(4), one F(5), and two equivalent F(2) atoms. The Na(2)-F(1) bond length is 2.22 Å. The Na(2)-F(4) bond length is 2.25 Å. The Na(2)-F(5) bond length is 2.24 Å. Both Na(2)-F(2) bond lengths are 2.27 Å. Hf(1) is bonded in a distorted pentagonal bipyramidal geometry to one F(1), one F(4), one F(5), two equivalent F(2), and two equivalent F(3) atoms. The Hf(1)-F(1) bond length is 2.04 Å. The Hf(1)-F(4) bond length is 2.07 Å. The Hf(1)-F(5) bond length is 2.06 Å. Both Hf(1)-F(2) bond lengths are 2.05 Å. Both Hf(1)-F(3) bond lengths are 2.03 Å. There are five inequivalent F sites. In the first F site, F(1) is bonded in a distorted rectangular see-saw-like geometry to one Na(2), two equivalent Na(1), and one Hf(1) atom. In the second F site, F(2) is bonded to one Na(2), two equivalent Na(1), and one Hf(1) atom to form a mixture of corner and edge-sharing FNa3Hf tetrahedra. In the third F site, F(3) is bonded in a 3-coordinate geometry to two equivalent Na(1) and one Hf(1) atom. In the fourth F site, F(4) is bonded to one Na(2), two equivalent Na(1), and one Hf(1) atom to form a mixture of corner and edge-sharing FNa3Hf tetrahedra. In the fifth F site, F(5) is bonded to one Na(2), two equivalent Na(1), and one Hf(1) atom to form a mixture of corner and edge-sharing FNa3Hf tetrahedra.