Sr3Mo2O7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. In the second Sr site, Sr(2) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, faces with four equivalent Sr(2)O12 cuboctahedra, and faces with eight equivalent Mo(1)O6 octahedra. Mo(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form MoO6 octahedra that share corners with five equivalent Mo(1)O6 octahedra and faces with four equivalent Sr(2)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 Mo(1) atoms to form distorted OSr4Mo2 octahedra that share corners with four equivalent O(3)Sr4Mo2 octahedra, corners with six equivalent O(2)Sr5Mo octahedra, corners with eight equivalent O(1)Sr4Mo2 octahedra, edges with three equivalent O(1)Sr4Mo2 octahedra, faces with two equivalent O(3)Sr4Mo2 octahedra, faces with two equivalent O(2)Sr5Mo octahedra, and faces with four equivalent O(1)Sr4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the second O site, O(2) is bonded to five equivalent Sr(1) and one Mo(1) atom to form OSr5Mo octahedra that share  a cornercorner with one O(3)Sr4Mo2 octahedra, corners with four equivalent O(2)Sr5Mo octahedra, corners with twelve equivalent O(1)Sr4Mo2 octahedra, edges with eight equivalent O(2)Sr5Mo octahedra, and faces with four equivalent O(1)Sr4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the third O site, O(3) is bonded to four equivalent Sr(2) and two equivalent Mo(1) atoms to form OSr4Mo2 octahedra that share corners with two equivalent O(2)Sr5Mo octahedra, corners with four equivalent O(3)Sr4Mo2 octahedra, corners with sixteen equivalent O(1)Sr4Mo2 octahedra, edges with four equivalent O(3)Sr4Mo2 octahedra, and faces with eight equivalent O(1)Sr4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°.
Sr3Mo2O7 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. All Sr(1)-O(1) bond lengths are 2.80 Å. There is one shorter (2.41 Å) and four longer (2.86 Å) Sr(1)-O(2) bond lengths. In the second Sr site, Sr(2) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form SrO12 cuboctahedra that share corners with four equivalent Sr(2)O12 cuboctahedra, faces with four equivalent Sr(2)O12 cuboctahedra, and faces with eight equivalent Mo(1)O6 octahedra. All Sr(2)-O(3) bond lengths are 2.85 Å. All Sr(2)-O(1) bond lengths are 2.89 Å. Mo(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form MoO6 octahedra that share corners with five equivalent Mo(1)O6 octahedra and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-2°. The Mo(1)-O(2) bond length is 2.12 Å. The Mo(1)-O(3) bond length is 2.11 Å. All Mo(1)-O(1) bond lengths are 2.01 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 Mo(1) atoms to form distorted OSr4Mo2 octahedra that share corners with four equivalent O(3)Sr4Mo2 octahedra, corners with six equivalent O(2)Sr5Mo octahedra, corners with eight equivalent O(1)Sr4Mo2 octahedra, edges with three equivalent O(1)Sr4Mo2 octahedra, faces with two equivalent O(3)Sr4Mo2 octahedra, faces with two equivalent O(2)Sr5Mo octahedra, and faces with four equivalent O(1)Sr4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°. In the second O site, O(2) is bonded to five equivalent Sr(1) and one Mo(1) atom to form OSr5Mo octahedra that share  a cornercorner with one O(3)Sr4Mo2 octahedra, corners with four equivalent O(2)Sr5Mo octahedra, corners with twelve equivalent O(1)Sr4Mo2 octahedra, edges with eight equivalent O(2)Sr5Mo octahedra, and faces with four equivalent O(1)Sr4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the third O site, O(3) is bonded to four equivalent Sr(2) and two equivalent Mo(1) atoms to form OSr4Mo2 octahedra that share corners with two equivalent O(2)Sr5Mo octahedra, corners with four equivalent O(3)Sr4Mo2 octahedra, corners with sixteen equivalent O(1)Sr4Mo2 octahedra, edges with four equivalent O(3)Sr4Mo2 octahedra, and faces with eight equivalent O(1)Sr4Mo2 octahedra. The corner-sharing octahedral tilt angles range from 0-61°.