Sr4MgNi2(O3Cl)2 crystallizes in the tetragonal P4mm space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to one O(4) and four equivalent O(3) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(4) atoms. In the third Sr site, Sr(3) is bonded in a 10-coordinate geometry to one Mg(1), four equivalent O(1), one Cl(2), and four equivalent Cl(1) atoms. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent Cl(2) atoms. Mg(1) is bonded in a 4-coordinate geometry to one Sr(3) and four equivalent O(1) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(1) atoms. In the second Ni site, Ni(2) is bonded in a distorted rectangular see-saw-like geometry to one O(4) and four equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(3), two equivalent Mg(1), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded to two equivalent Sr(2), two equivalent Sr(4), and two equivalent Ni(2) atoms to form a mixture of distorted face, corner, and edge-sharing OSr4Ni2 octahedra. The corner-sharing octahedral tilt angles are 7°. In the third O site, O(3) is bonded in a 5-coordinate geometry to four equivalent Sr(1) and one Ni(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(1), four equivalent Sr(2), and one Ni(2) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a distorted square co-planar geometry to four equivalent Sr(3) atoms. In the second Cl site, Cl(2) is bonded in a 5-coordinate geometry to one Sr(3) and four equivalent Sr(4) atoms.
Sr4MgNi2(O3Cl)2 crystallizes in the tetragonal P4mm space group. There are four inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 5-coordinate geometry to one O(4) and four equivalent O(3) atoms. The Sr(1)-O(4) bond length is 2.20 Å. All Sr(1)-O(3) bond lengths are 2.85 Å. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent O(4) atoms. All Sr(2)-O(2) bond lengths are 2.69 Å. All Sr(2)-O(4) bond lengths are 2.86 Å. In the third Sr site, Sr(3) is bonded in a 10-coordinate geometry to one Mg(1), four equivalent O(1), one Cl(2), and four equivalent Cl(1) atoms. The Sr(3)-Mg(1) bond length is 2.78 Å. All Sr(3)-O(1) bond lengths are 2.96 Å. The Sr(3)-Cl(2) bond length is 3.04 Å. All Sr(3)-Cl(1) bond lengths are 2.87 Å. In the fourth Sr site, Sr(4) is bonded in a 8-coordinate geometry to four equivalent O(2) and four equivalent Cl(2) atoms. All Sr(4)-O(2) bond lengths are 2.50 Å. All Sr(4)-Cl(2) bond lengths are 3.16 Å. Mg(1) is bonded in a 4-coordinate geometry to one Sr(3) and four equivalent O(1) atoms. All Mg(1)-O(1) bond lengths are 2.01 Å. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(3) and four equivalent O(1) atoms. The Ni(1)-O(3) bond length is 2.08 Å. All Ni(1)-O(1) bond lengths are 2.05 Å. In the second Ni site, Ni(2) is bonded in a distorted rectangular see-saw-like geometry to one O(4) and four equivalent O(2) atoms. The Ni(2)-O(4) bond length is 2.58 Å. All Ni(2)-O(2) bond lengths are 1.94 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(3), two equivalent Mg(1), and two equivalent Ni(1) atoms. In the second O site, O(2) is bonded to two equivalent Sr(2), two equivalent Sr(4), and two equivalent Ni(2) atoms to form a mixture of distorted face, corner, and edge-sharing OSr4Ni2 octahedra. The corner-sharing octahedral tilt angles are 7°. In the third O site, O(3) is bonded in a 5-coordinate geometry to four equivalent Sr(1) and one Ni(1) atom. In the fourth O site, O(4) is bonded in a 6-coordinate geometry to one Sr(1), four equivalent Sr(2), and one Ni(2) atom. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded in a distorted square co-planar geometry to four equivalent Sr(3) atoms. In the second Cl site, Cl(2) is bonded in a 5-coordinate geometry to one Sr(3) and four equivalent Sr(4) atoms.