Sr2YTi2O7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form distorted SrO6 pentagonal pyramids that share corners with six equivalent Sr(1)O6 pentagonal pyramids, corners with four equivalent Ti(1)O5 trigonal bipyramids, edges with three equivalent Sr(1)O6 pentagonal pyramids, and faces with two equivalent Sr(1)O6 pentagonal pyramids. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. Ti(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted TiO5 trigonal bipyramids that share corners with four equivalent Sr(1)O6 pentagonal pyramids and corners with four equivalent Ti(1)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a square co-planar geometry to four equivalent Sr(1) atoms. In the second O site, O(2) is bonded to two equivalent Y(1) and two equivalent Ti(1) atoms to form a mixture of distorted corner and edge-sharing OY2Ti2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Y(1) and two equivalent Ti(1) atoms to form a mixture of distorted corner and edge-sharing OY2Ti2 trigonal pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to four equivalent Sr(1) and one Ti(1) atom.
Sr2YTi2O7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form distorted SrO6 pentagonal pyramids that share corners with six equivalent Sr(1)O6 pentagonal pyramids, corners with four equivalent Ti(1)O5 trigonal bipyramids, edges with three equivalent Sr(1)O6 pentagonal pyramids, and faces with two equivalent Sr(1)O6 pentagonal pyramids. There is one shorter (2.36 Å) and one longer (2.40 Å) Sr(1)-O(1) bond length. There are a spread of Sr(1)-O(4) bond distances ranging from 2.55-3.05 Å. Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. All Y(1)-O(2) bond lengths are 2.36 Å. There are two shorter (2.44 Å) and two longer (2.45 Å) Y(1)-O(3) bond lengths. Ti(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted TiO5 trigonal bipyramids that share corners with four equivalent Sr(1)O6 pentagonal pyramids and corners with four equivalent Ti(1)O5 trigonal bipyramids. The Ti(1)-O(4) bond length is 1.79 Å. Both Ti(1)-O(2) bond lengths are 1.98 Å. Both Ti(1)-O(3) bond lengths are 1.98 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a square co-planar geometry to four equivalent Sr(1) atoms. In the second O site, O(2) is bonded to two equivalent Y(1) and two equivalent Ti(1) atoms to form a mixture of distorted corner and edge-sharing OY2Ti2 tetrahedra. In the third O site, O(3) is bonded to two equivalent Y(1) and two equivalent Ti(1) atoms to form a mixture of distorted corner and edge-sharing OY2Ti2 trigonal pyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to four equivalent Sr(1) and one Ti(1) atom.