Sr3Zr2O7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Zr(1)O6 octahedra. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. Zr(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form ZrO6 octahedra that share corners with five equivalent Zr(1)O6 octahedra and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Zr(1) atoms to form distorted OSr4Zr2 octahedra that share corners with six equivalent O(2)Sr5Zr octahedra, corners with eight equivalent O(1)Sr4Zr2 octahedra, edges with three equivalent O(1)Sr4Zr2 octahedra, faces with two equivalent O(2)Sr5Zr octahedra, and faces with four equivalent O(1)Sr4Zr2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the second O site, O(2) is bonded to five equivalent Sr(2) and one Zr(1) atom to form distorted OSr5Zr octahedra that share corners with four equivalent O(2)Sr5Zr octahedra, corners with twelve equivalent O(1)Sr4Zr2 octahedra, edges with eight equivalent O(2)Sr5Zr octahedra, and faces with four equivalent O(1)Sr4Zr2 octahedra. The corner-sharing octahedral tilt angles range from 11-54°. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Zr(1) atoms.
Sr3Zr2O7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, and faces with eight equivalent Zr(1)O6 octahedra. All Sr(1)-O(3) bond lengths are 2.96 Å. All Sr(1)-O(1) bond lengths are 2.95 Å. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. All Sr(2)-O(1) bond lengths are 2.80 Å. There is one shorter (2.41 Å) and four longer (2.98 Å) Sr(2)-O(2) bond lengths. Zr(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form ZrO6 octahedra that share corners with five equivalent Zr(1)O6 octahedra and faces with four equivalent Sr(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. The Zr(1)-O(2) bond length is 2.10 Å. The Zr(1)-O(3) bond length is 2.12 Å. All Zr(1)-O(1) bond lengths are 2.10 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Zr(1) atoms to form distorted OSr4Zr2 octahedra that share corners with six equivalent O(2)Sr5Zr octahedra, corners with eight equivalent O(1)Sr4Zr2 octahedra, edges with three equivalent O(1)Sr4Zr2 octahedra, faces with two equivalent O(2)Sr5Zr octahedra, and faces with four equivalent O(1)Sr4Zr2 octahedra. The corner-sharing octahedral tilt angles range from 0-60°. In the second O site, O(2) is bonded to five equivalent Sr(2) and one Zr(1) atom to form distorted OSr5Zr octahedra that share corners with four equivalent O(2)Sr5Zr octahedra, corners with twelve equivalent O(1)Sr4Zr2 octahedra, edges with eight equivalent O(2)Sr5Zr octahedra, and faces with four equivalent O(1)Sr4Zr2 octahedra. The corner-sharing octahedral tilt angles range from 11-54°. In the third O site, O(3) is bonded in a distorted linear geometry to four equivalent Sr(1) and two equivalent Zr(1) atoms.