Sr2CrFeAsO3 crystallizes in the tetragonal P4/nmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 4-coordinate geometry to four equivalent As(1) and four equivalent O(1) atoms. 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. Cr(1) is bonded to one O(2) and four equivalent O(1) atoms to form corner-sharing CrO5 square pyramids. Fe(1) is bonded to four equivalent As(1) atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. As(1) is bonded in a 8-coordinate geometry to four equivalent Sr(1) and four equivalent Fe(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cr(1) atoms to form distorted OSr4Cr2 octahedra that share corners with two equivalent O(1)Sr4Cr2 octahedra, corners with six equivalent O(2)Sr5Cr octahedra, edges with two equivalent O(1)Sr4Cr2 octahedra, faces with two equivalent O(2)Sr5Cr octahedra, and faces with four equivalent O(1)Sr4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 16-55°. In the second O site, O(2) is bonded to five equivalent Sr(2) and one Cr(1) atom to form distorted OSr5Cr octahedra that share corners with four equivalent O(2)Sr5Cr octahedra, corners with twelve equivalent O(1)Sr4Cr2 octahedra, edges with eight equivalent O(2)Sr5Cr octahedra, and faces with four equivalent O(1)Sr4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 11-55°.
Sr2CrFeAsO3 crystallizes in the tetragonal P4/nmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 4-coordinate geometry to four equivalent As(1) and four equivalent O(1) atoms. All Sr(1)-As(1) bond lengths are 3.25 Å. All Sr(1)-O(1) bond lengths are 2.51 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 2.73 Å. There is one shorter (2.46 Å) and four longer (2.77 Å) Sr(2)-O(2) bond lengths. Cr(1) is bonded to one O(2) and four equivalent O(1) atoms to form corner-sharing CrO5 square pyramids. The Cr(1)-O(2) bond length is 1.89 Å. All Cr(1)-O(1) bond lengths are 1.97 Å. Fe(1) is bonded to four equivalent As(1) atoms to form a mixture of edge and corner-sharing FeAs4 tetrahedra. All Fe(1)-As(1) bond lengths are 2.33 Å. As(1) is bonded in a 8-coordinate geometry to four equivalent Sr(1) and four equivalent Fe(1) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), and two equivalent Cr(1) atoms to form distorted OSr4Cr2 octahedra that share corners with two equivalent O(1)Sr4Cr2 octahedra, corners with six equivalent O(2)Sr5Cr octahedra, edges with two equivalent O(1)Sr4Cr2 octahedra, faces with two equivalent O(2)Sr5Cr octahedra, and faces with four equivalent O(1)Sr4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 16-55°. In the second O site, O(2) is bonded to five equivalent Sr(2) and one Cr(1) atom to form distorted OSr5Cr octahedra that share corners with four equivalent O(2)Sr5Cr octahedra, corners with twelve equivalent O(1)Sr4Cr2 octahedra, edges with eight equivalent O(2)Sr5Cr octahedra, and faces with four equivalent O(1)Sr4Cr2 octahedra. The corner-sharing octahedral tilt angles range from 11-55°.