Sr3CuPtO6 crystallizes in the monoclinic C2/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent O(2), three equivalent O(1), and three equivalent O(3) atoms. Pt(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), three equivalent Sr(2), one Pt(1), and one Cu(1) atom to form distorted OSr4CuPt octahedra that share corners with four equivalent O(1)Sr4CuPt octahedra, corners with seven equivalent O(2)Sr4Pt square pyramids,  an edgeedge with one O(1)Sr4CuPt octahedra,  an edgeedge with one O(2)Sr4Pt square pyramid,  a faceface with one O(1)Sr4CuPt octahedra, and  a faceface with one O(2)Sr4Pt square pyramid. The corner-sharing octahedral tilt angles range from 0-67°. In the second O site, O(2) is bonded to two equivalent Sr(1), two equivalent Sr(2), and one Pt(1) atom to form OSr4Pt square pyramids that share corners with seven equivalent O(1)Sr4CuPt octahedra, corners with three equivalent O(2)Sr4Pt square pyramids,  an edgeedge with one O(1)Sr4CuPt octahedra, edges with three equivalent O(2)Sr4Pt square pyramids, and  a faceface with one O(1)Sr4CuPt octahedra. The corner-sharing octahedral tilt angles range from 26-65°. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Sr(1), three equivalent Sr(2), one Pt(1), and one Cu(1) atom.
Sr3CuPtO6 crystallizes in the monoclinic C2/c space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms. Both Sr(1)-O(1) bond lengths are 2.82 Å. Both Sr(1)-O(3) bond lengths are 2.90 Å. There are two shorter (2.48 Å) and two longer (2.61 Å) Sr(1)-O(2) bond lengths. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent O(2), three equivalent O(1), and three equivalent O(3) atoms. There is one shorter (2.48 Å) and one longer (2.64 Å) Sr(2)-O(2) bond length. There are a spread of Sr(2)-O(1) bond distances ranging from 2.52-2.86 Å. There are a spread of Sr(2)-O(3) bond distances ranging from 2.54-2.81 Å. Pt(1) is bonded in an octahedral geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Pt(1)-O(1) bond lengths are 2.05 Å. Both Pt(1)-O(2) bond lengths are 2.07 Å. Both Pt(1)-O(3) bond lengths are 2.05 Å. Cu(1) is bonded in a square co-planar geometry to two equivalent O(1) and two equivalent O(3) atoms. Both Cu(1)-O(1) bond lengths are 2.02 Å. Both Cu(1)-O(3) bond lengths are 2.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Sr(1), three equivalent Sr(2), one Pt(1), and one Cu(1) atom to form distorted OSr4CuPt octahedra that share corners with four equivalent O(1)Sr4CuPt octahedra, corners with seven equivalent O(2)Sr4Pt square pyramids,  an edgeedge with one O(1)Sr4CuPt octahedra,  an edgeedge with one O(2)Sr4Pt square pyramid,  a faceface with one O(1)Sr4CuPt octahedra, and  a faceface with one O(2)Sr4Pt square pyramid. The corner-sharing octahedral tilt angles range from 0-67°. In the second O site, O(2) is bonded to two equivalent Sr(1), two equivalent Sr(2), and one Pt(1) atom to form OSr4Pt square pyramids that share corners with seven equivalent O(1)Sr4CuPt octahedra, corners with three equivalent O(2)Sr4Pt square pyramids,  an edgeedge with one O(1)Sr4CuPt octahedra, edges with three equivalent O(2)Sr4Pt square pyramids, and  a faceface with one O(1)Sr4CuPt octahedra. The corner-sharing octahedral tilt angles range from 26-65°. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Sr(1), three equivalent Sr(2), one Pt(1), and one Cu(1) atom.