Sr2CuSe2(O3Cl)2 crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(3), three equivalent O(2), and three equivalent Cl(1) atoms. Cu(1) is bonded in a distorted octahedral geometry to two equivalent O(1), two equivalent O(3), and two equivalent Cl(1) atoms. Se(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to three equivalent Sr(1) and one Se(1) atom. In the third O site, O(3) is bonded to two equivalent Sr(1), one Cu(1), and one Se(1) atom to form distorted corner-sharing OSr2CuSe tetrahedra. Cl(1) is bonded in a distorted see-saw-like geometry to three equivalent Sr(1) and one Cu(1) atom.
Sr2CuSe2(O3Cl)2 crystallizes in the monoclinic P2_1/c space group. Sr(1) is bonded in a 10-coordinate geometry to two equivalent O(1), two equivalent O(3), three equivalent O(2), and three equivalent Cl(1) atoms. There is one shorter (2.76 Å) and one longer (2.82 Å) Sr(1)-O(1) bond length. There is one shorter (2.64 Å) and one longer (2.99 Å) Sr(1)-O(3) bond length. There are a spread of Sr(1)-O(2) bond distances ranging from 2.58-3.24 Å. There are a spread of Sr(1)-Cl(1) bond distances ranging from 3.04-3.27 Å. Cu(1) is bonded in a distorted octahedral geometry to two equivalent O(1), two equivalent O(3), and two equivalent Cl(1) atoms. Both Cu(1)-O(1) bond lengths are 2.02 Å. Both Cu(1)-O(3) bond lengths are 2.01 Å. Both Cu(1)-Cl(1) bond lengths are 2.77 Å. Se(1) is bonded in a distorted trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Se(1)-O(1) bond length is 1.76 Å. The Se(1)-O(2) bond length is 1.69 Å. The Se(1)-O(3) bond length is 1.76 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1), one Cu(1), and one Se(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to three equivalent Sr(1) and one Se(1) atom. In the third O site, O(3) is bonded to two equivalent Sr(1), one Cu(1), and one Se(1) atom to form distorted corner-sharing OSr2CuSe tetrahedra. Cl(1) is bonded in a distorted see-saw-like geometry to three equivalent Sr(1) and one Cu(1) atom.