Sr2MgCo2O5 crystallizes in the triclinic P1 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. In the second Co site, Co(2) is bonded in a distorted trigonal pyramidal geometry to one O(2), one O(3), one O(4), and one O(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), one Sr(2), one Mg(1), and one Co(1) atom to form distorted corner-sharing OSr2MgCo tetrahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Sr(2), two equivalent Sr(1), one Mg(1), one Co(1), and one Co(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(2), one Mg(1), one Co(1), and one Co(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(2), one Mg(1), one Co(1), and one Co(2) atom. In the fifth O site, O(5) is bonded to one Sr(1), one Sr(2), one Mg(1), one Co(1), and one Co(2) atom to form distorted corner-sharing OSr2MgCo2 trigonal bipyramids.
Sr2MgCo2O5 crystallizes in the triclinic P1 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 6-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms. The Sr(1)-O(1) bond length is 2.36 Å. The Sr(1)-O(3) bond length is 2.55 Å. The Sr(1)-O(4) bond length is 2.64 Å. The Sr(1)-O(5) bond length is 2.83 Å. There is one shorter (2.64 Å) and one longer (3.01 Å) Sr(1)-O(2) bond length. In the second Sr site, Sr(2) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Sr(2)-O(1) bond length is 2.37 Å. The Sr(2)-O(2) bond length is 2.55 Å. The Sr(2)-O(3) bond length is 2.56 Å. The Sr(2)-O(4) bond length is 2.49 Å. The Sr(2)-O(5) bond length is 2.45 Å. Mg(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Mg(1)-O(1) bond length is 1.97 Å. The Mg(1)-O(2) bond length is 2.42 Å. The Mg(1)-O(3) bond length is 2.02 Å. The Mg(1)-O(4) bond length is 2.08 Å. The Mg(1)-O(5) bond length is 2.13 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded in a 5-coordinate geometry to one O(1), one O(2), one O(3), one O(4), and one O(5) atom. The Co(1)-O(1) bond length is 1.93 Å. The Co(1)-O(2) bond length is 2.15 Å. The Co(1)-O(3) bond length is 2.57 Å. The Co(1)-O(4) bond length is 2.15 Å. The Co(1)-O(5) bond length is 1.99 Å. In the second Co site, Co(2) is bonded in a distorted trigonal pyramidal geometry to one O(2), one O(3), one O(4), and one O(5) atom. The Co(2)-O(2) bond length is 2.09 Å. The Co(2)-O(3) bond length is 2.00 Å. The Co(2)-O(4) bond length is 1.99 Å. The Co(2)-O(5) bond length is 2.01 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), one Sr(2), one Mg(1), and one Co(1) atom to form distorted corner-sharing OSr2MgCo tetrahedra. In the second O site, O(2) is bonded in a 6-coordinate geometry to one Sr(2), two equivalent Sr(1), one Mg(1), one Co(1), and one Co(2) atom. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(2), one Mg(1), one Co(1), and one Co(2) atom. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Sr(1), one Sr(2), one Mg(1), one Co(1), and one Co(2) atom. In the fifth O site, O(5) is bonded to one Sr(1), one Sr(2), one Mg(1), one Co(1), and one Co(2) atom to form distorted corner-sharing OSr2MgCo2 trigonal bipyramids.