NaCaMg2F7 crystallizes in the orthorhombic Imma space group. Na(1) is bonded to two equivalent F(1), two equivalent F(4), and four equivalent F(3) atoms to form distorted NaF8 hexagonal bipyramids that share edges with two equivalent Na(1)F8 hexagonal bipyramids, edges with four equivalent Ca(1)F8 hexagonal bipyramids, edges with two equivalent Mg(1)F6 octahedra, and edges with four equivalent Mg(2)F6 octahedra. Ca(1) is bonded to two equivalent F(2), two equivalent F(4), and four equivalent F(3) atoms to form distorted CaF8 hexagonal bipyramids that share edges with two equivalent Ca(1)F8 hexagonal bipyramids, edges with four equivalent Na(1)F8 hexagonal bipyramids, edges with two equivalent Mg(2)F6 octahedra, and edges with four equivalent Mg(1)F6 octahedra. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent F(2) and four equivalent F(3) atoms to form MgF6 octahedra that share corners with two equivalent Mg(1)F6 octahedra, corners with four equivalent Mg(2)F6 octahedra, edges with two equivalent Na(1)F8 hexagonal bipyramids, and edges with four equivalent Ca(1)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 48-50°. In the second Mg site, Mg(2) is bonded to two equivalent F(1) and four equivalent F(3) atoms to form MgF6 octahedra that share corners with two equivalent Mg(2)F6 octahedra, corners with four equivalent Mg(1)F6 octahedra, edges with two equivalent Ca(1)F8 hexagonal bipyramids, and edges with four equivalent Na(1)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-48°. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Mg(2) atoms. In the second F site, F(2) is bonded to two equivalent Ca(1) and two equivalent Mg(1) atoms to form distorted FCa2Mg2 tetrahedra that share corners with two equivalent F(4)Na2Ca2 tetrahedra, corners with four equivalent F(2)Ca2Mg2 tetrahedra, and  an edgeedge with one F(4)Na2Ca2 tetrahedra. In the third F site, F(3) is bonded in a 4-coordinate geometry to one Na(1), one Ca(1), one Mg(1), and one Mg(2) atom. In the fourth F site, F(4) is bonded to two equivalent Na(1) and two equivalent Ca(1) atoms to form FNa2Ca2 tetrahedra that share corners with two equivalent F(2)Ca2Mg2 tetrahedra, corners with four equivalent F(4)Na2Ca2 tetrahedra, and  an edgeedge with one F(2)Ca2Mg2 tetrahedra.
NaCaMg2F7 crystallizes in the orthorhombic Imma space group. Na(1) is bonded to two equivalent F(1), two equivalent F(4), and four equivalent F(3) atoms to form distorted NaF8 hexagonal bipyramids that share edges with two equivalent Na(1)F8 hexagonal bipyramids, edges with four equivalent Ca(1)F8 hexagonal bipyramids, edges with two equivalent Mg(1)F6 octahedra, and edges with four equivalent Mg(2)F6 octahedra. Both Na(1)-F(1) bond lengths are 2.58 Å. Both Na(1)-F(4) bond lengths are 2.26 Å. All Na(1)-F(3) bond lengths are 2.64 Å. Ca(1) is bonded to two equivalent F(2), two equivalent F(4), and four equivalent F(3) atoms to form distorted CaF8 hexagonal bipyramids that share edges with two equivalent Ca(1)F8 hexagonal bipyramids, edges with four equivalent Na(1)F8 hexagonal bipyramids, edges with two equivalent Mg(2)F6 octahedra, and edges with four equivalent Mg(1)F6 octahedra. Both Ca(1)-F(2) bond lengths are 2.56 Å. Both Ca(1)-F(4) bond lengths are 2.24 Å. All Ca(1)-F(3) bond lengths are 2.48 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent F(2) and four equivalent F(3) atoms to form MgF6 octahedra that share corners with two equivalent Mg(1)F6 octahedra, corners with four equivalent Mg(2)F6 octahedra, edges with two equivalent Na(1)F8 hexagonal bipyramids, and edges with four equivalent Ca(1)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 48-50°. Both Mg(1)-F(2) bond lengths are 2.00 Å. All Mg(1)-F(3) bond lengths are 2.01 Å. In the second Mg site, Mg(2) is bonded to two equivalent F(1) and four equivalent F(3) atoms to form MgF6 octahedra that share corners with two equivalent Mg(2)F6 octahedra, corners with four equivalent Mg(1)F6 octahedra, edges with two equivalent Ca(1)F8 hexagonal bipyramids, and edges with four equivalent Na(1)F8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-48°. Both Mg(2)-F(1) bond lengths are 2.01 Å. All Mg(2)-F(3) bond lengths are 2.01 Å. There are four inequivalent F sites. In the first F site, F(1) is bonded in a 4-coordinate geometry to two equivalent Na(1) and two equivalent Mg(2) atoms. In the second F site, F(2) is bonded to two equivalent Ca(1) and two equivalent Mg(1) atoms to form distorted FCa2Mg2 tetrahedra that share corners with two equivalent F(4)Na2Ca2 tetrahedra, corners with four equivalent F(2)Ca2Mg2 tetrahedra, and  an edgeedge with one F(4)Na2Ca2 tetrahedra. In the third F site, F(3) is bonded in a 4-coordinate geometry to one Na(1), one Ca(1), one Mg(1), and one Mg(2) atom. In the fourth F site, F(4) is bonded to two equivalent Na(1) and two equivalent Ca(1) atoms to form FNa2Ca2 tetrahedra that share corners with two equivalent F(2)Ca2Mg2 tetrahedra, corners with four equivalent F(4)Na2Ca2 tetrahedra, and  an edgeedge with one F(2)Ca2Mg2 tetrahedra.