YSr2AlCu2O7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and three equivalent O(4) atoms. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. Cu(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted CuO5 square pyramids that share corners with four equivalent Cu(1)O5 square pyramids and  a cornercorner with one Al(1)O4 tetrahedra. Al(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form AlO4 tetrahedra that share corners with two equivalent Cu(1)O5 square pyramids and corners with two equivalent Al(1)O4 tetrahedra. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to three equivalent Sr(1), one Cu(1), and one Al(1) atom. In the second O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Al(1) atoms. In the third O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cu(1) atoms. In the fourth O site, O(3) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cu(1) atoms to form a mixture of distorted face and corner-sharing OSr2Y2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 1-67°.
YSr2AlCu2O7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 8-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and three equivalent O(4) atoms. The Sr(1)-O(1) bond length is 2.54 Å. There is one shorter (2.83 Å) and one longer (2.86 Å) Sr(1)-O(2) bond length. There is one shorter (2.76 Å) and one longer (2.83 Å) Sr(1)-O(3) bond length. There are a spread of Sr(1)-O(4) bond distances ranging from 2.43-3.02 Å. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. There are two shorter (2.36 Å) and two longer (2.40 Å) Y(1)-O(2) bond lengths. There are two shorter (2.45 Å) and two longer (2.52 Å) Y(1)-O(3) bond lengths. Cu(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted CuO5 square pyramids that share corners with four equivalent Cu(1)O5 square pyramids and  a cornercorner with one Al(1)O4 tetrahedra. The Cu(1)-O(4) bond length is 2.50 Å. Both Cu(1)-O(2) bond lengths are 1.96 Å. Both Cu(1)-O(3) bond lengths are 1.94 Å. Al(1) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form AlO4 tetrahedra that share corners with two equivalent Cu(1)O5 square pyramids and corners with two equivalent Al(1)O4 tetrahedra. There is one shorter (1.80 Å) and one longer (1.81 Å) Al(1)-O(1) bond length. Both Al(1)-O(4) bond lengths are 1.76 Å. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to three equivalent Sr(1), one Cu(1), and one Al(1) atom. In the second O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Al(1) atoms. In the third O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cu(1) atoms. In the fourth O site, O(3) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Cu(1) atoms to form a mixture of distorted face and corner-sharing OSr2Y2Cu2 octahedra. The corner-sharing octahedral tilt angles range from 1-67°.