MgNb3O7F crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(2), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing MgO5 trigonal bipyramids. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(3), one O(6), two equivalent O(4), and two equivalent O(5) atoms. In the third Nb site, Nb(3) is bonded to one O(1), one O(6), two equivalent O(7), and two equivalent F(1) atoms to form corner-sharing NbO4F2 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Nb(1) and one Nb(3) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nb(2) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Nb(1), and two equivalent Nb(2) atoms to form distorted corner-sharing OMg2Nb3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(2) and one Nb(3) atom. In the seventh O site, O(7) is bonded in a linear geometry to two equivalent Nb(3) atoms. F(1) is bonded in a linear geometry to two equivalent Nb(3) atoms.
MgNb3O7F crystallizes in the monoclinic Pm space group. Mg(1) is bonded to one O(2), two equivalent O(4), and two equivalent O(5) atoms to form corner-sharing MgO5 trigonal bipyramids. The Mg(1)-O(2) bond length is 1.97 Å. Both Mg(1)-O(4) bond lengths are 2.09 Å. There is one shorter (2.08 Å) and one longer (2.09 Å) Mg(1)-O(5) bond length. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 6-coordinate geometry to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms. The Nb(1)-O(1) bond length is 1.83 Å. The Nb(1)-O(4) bond length is 2.55 Å. Both Nb(1)-O(2) bond lengths are 2.09 Å. There is one shorter (2.05 Å) and one longer (2.07 Å) Nb(1)-O(3) bond length. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one O(3), one O(6), two equivalent O(4), and two equivalent O(5) atoms. The Nb(2)-O(3) bond length is 2.55 Å. The Nb(2)-O(6) bond length is 1.82 Å. Both Nb(2)-O(4) bond lengths are 2.06 Å. Both Nb(2)-O(5) bond lengths are 2.08 Å. In the third Nb site, Nb(3) is bonded to one O(1), one O(6), two equivalent O(7), and two equivalent F(1) atoms to form corner-sharing NbO4F2 octahedra. The corner-sharing octahedral tilt angles range from 1-4°. The Nb(3)-O(1) bond length is 2.02 Å. The Nb(3)-O(6) bond length is 2.08 Å. There is one shorter (1.92 Å) and one longer (1.98 Å) Nb(3)-O(7) bond length. Both Nb(3)-F(1) bond lengths are 2.07 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Nb(1) and one Nb(3) atom. In the second O site, O(2) is bonded in a T-shaped geometry to one Mg(1) and two equivalent Nb(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nb(2) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Mg(1), one Nb(1), and two equivalent Nb(2) atoms to form distorted corner-sharing OMg2Nb3 trigonal bipyramids. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Nb(2) atoms. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(2) and one Nb(3) atom. In the seventh O site, O(7) is bonded in a linear geometry to two equivalent Nb(3) atoms. F(1) is bonded in a linear geometry to two equivalent Nb(3) atoms.