Na2NiFeF7 crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(4), and two equivalent F(5) atoms. In the second Na site, Na(2) is bonded to one F(2), one F(3), one F(5), one F(6), two equivalent F(1), and two equivalent F(4) atoms to form distorted NaF8 hexagonal bipyramids that share corners with two equivalent Na(2)F8 hexagonal bipyramids, corners with two equivalent Fe(1)F6 octahedra, edges with two equivalent Fe(1)F6 octahedra, and edges with four equivalent Ni(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 53-55°. Fe(1) is bonded to one F(2), one F(5), two equivalent F(1), and two equivalent F(4) atoms to form FeF6 octahedra that share corners with two equivalent Na(2)F8 hexagonal bipyramids, corners with four equivalent Ni(1)F6 octahedra, and edges with two equivalent Na(2)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 42°. Ni(1) is bonded to one F(3), one F(6), two equivalent F(1), and two equivalent F(4) atoms to form NiF6 octahedra that share corners with two equivalent Ni(1)F6 octahedra, corners with four equivalent Fe(1)F6 octahedra, and edges with four equivalent Na(2)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-46°. There are six inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one Ni(1) atom. In the second F site, F(2) is bonded to one Na(2), two equivalent Na(1), and one Fe(1) atom to form a mixture of distorted edge and corner-sharing FNa3Fe tetrahedra. In the third F site, F(3) is bonded in a 2-coordinate geometry to two equivalent Na(2) and two equivalent Ni(1) atoms. In the fourth F site, F(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one Ni(1) atom. In the fifth F site, F(5) is bonded to one Na(2), two equivalent Na(1), and one Fe(1) atom to form a mixture of distorted edge and corner-sharing FNa3Fe tetrahedra. In the sixth F site, F(6) is bonded in a 2-coordinate geometry to two equivalent Na(2) and two equivalent Ni(1) atoms.
Na2NiFeF7 crystallizes in the orthorhombic Imm2 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 8-coordinate geometry to two equivalent F(1), two equivalent F(2), two equivalent F(4), and two equivalent F(5) atoms. Both Na(1)-F(1) bond lengths are 2.73 Å. Both Na(1)-F(2) bond lengths are 2.45 Å. Both Na(1)-F(4) bond lengths are 2.85 Å. Both Na(1)-F(5) bond lengths are 2.48 Å. In the second Na site, Na(2) is bonded to one F(2), one F(3), one F(5), one F(6), two equivalent F(1), and two equivalent F(4) atoms to form distorted NaF8 hexagonal bipyramids that share corners with two equivalent Na(2)F8 hexagonal bipyramids, corners with two equivalent Fe(1)F6 octahedra, edges with two equivalent Fe(1)F6 octahedra, and edges with four equivalent Ni(1)F6 octahedra. The corner-sharing octahedral tilt angles range from 53-55°. The Na(2)-F(2) bond length is 2.26 Å. The Na(2)-F(3) bond length is 2.87 Å. The Na(2)-F(5) bond length is 2.26 Å. The Na(2)-F(6) bond length is 2.80 Å. Both Na(2)-F(1) bond lengths are 2.57 Å. Both Na(2)-F(4) bond lengths are 2.53 Å. Fe(1) is bonded to one F(2), one F(5), two equivalent F(1), and two equivalent F(4) atoms to form FeF6 octahedra that share corners with two equivalent Na(2)F8 hexagonal bipyramids, corners with four equivalent Ni(1)F6 octahedra, and edges with two equivalent Na(2)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 42°. The Fe(1)-F(2) bond length is 1.99 Å. The Fe(1)-F(5) bond length is 1.98 Å. Both Fe(1)-F(1) bond lengths are 1.95 Å. Both Fe(1)-F(4) bond lengths are 1.95 Å. Ni(1) is bonded to one F(3), one F(6), two equivalent F(1), and two equivalent F(4) atoms to form NiF6 octahedra that share corners with two equivalent Ni(1)F6 octahedra, corners with four equivalent Fe(1)F6 octahedra, and edges with four equivalent Na(2)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 42-46°. The Ni(1)-F(3) bond length is 1.98 Å. The Ni(1)-F(6) bond length is 1.98 Å. Both Ni(1)-F(1) bond lengths are 2.02 Å. Both Ni(1)-F(4) bond lengths are 2.02 Å. There are six inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one Ni(1) atom. In the second F site, F(2) is bonded to one Na(2), two equivalent Na(1), and one Fe(1) atom to form a mixture of distorted edge and corner-sharing FNa3Fe tetrahedra. In the third F site, F(3) is bonded in a 2-coordinate geometry to two equivalent Na(2) and two equivalent Ni(1) atoms. In the fourth F site, F(4) is bonded in a 4-coordinate geometry to one Na(1), one Na(2), one Fe(1), and one Ni(1) atom. In the fifth F site, F(5) is bonded to one Na(2), two equivalent Na(1), and one Fe(1) atom to form a mixture of distorted edge and corner-sharing FNa3Fe tetrahedra. In the sixth F site, F(6) is bonded in a 2-coordinate geometry to two equivalent Na(2) and two equivalent Ni(1) atoms.