Sr4FeRuO8 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Cmmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to two equivalent O(3), three equivalent O(2), and four equivalent O(1) atoms. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to two equivalent O(2), three equivalent O(3), and four equivalent O(1) atoms. Ru(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form RuO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedra are not tilted. Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with four equivalent Ru(1)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sr(1), two equivalent Sr(2), one Ru(1), and one Fe(1) atom to form distorted OSr4FeRu octahedra that share corners with two equivalent O(1)Sr4FeRu octahedra, corners with six equivalent O(2)Sr5Fe octahedra, corners with six equivalent O(3)Sr5Ru octahedra, edges with two equivalent O(1)Sr4FeRu octahedra, faces with two equivalent O(2)Sr5Fe octahedra, faces with two equivalent O(3)Sr5Ru octahedra, and faces with four equivalent O(1)Sr4FeRu octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the second O site, O(2) is bonded to two equivalent Sr(2), three equivalent Sr(1), and one Fe(1) atom to form distorted OSr5Fe octahedra that share corners with five equivalent O(2)Sr5Fe octahedra, corners with twelve equivalent O(1)Sr4FeRu octahedra, edges with two equivalent O(2)Sr5Fe octahedra, edges with six equivalent O(3)Sr5Ru octahedra, and faces with four equivalent O(1)Sr4FeRu octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the third O site, O(3) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Ru(1) atom to form OSr5Ru octahedra that share corners with five equivalent O(3)Sr5Ru octahedra, corners with twelve equivalent O(1)Sr4FeRu octahedra, edges with two equivalent O(3)Sr5Ru octahedra, edges with six equivalent O(2)Sr5Fe octahedra, and faces with four equivalent O(1)Sr4FeRu octahedra. The corner-sharing octahedral tilt angles range from 0-56°.
Sr4FeRuO8 is (La,Ba)CuO4-derived structured and crystallizes in the orthorhombic Cmmm space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 9-coordinate geometry to two equivalent O(3), three equivalent O(2), and four equivalent O(1) atoms. Both Sr(1)-O(3) bond lengths are 2.80 Å. There is one shorter (2.45 Å) and two longer (2.81 Å) Sr(1)-O(2) bond lengths. All Sr(1)-O(1) bond lengths are 2.71 Å. In the second Sr site, Sr(2) is bonded in a 9-coordinate geometry to two equivalent O(2), three equivalent O(3), and four equivalent O(1) atoms. Both Sr(2)-O(2) bond lengths are 2.81 Å. There is one shorter (2.48 Å) and two longer (2.81 Å) Sr(2)-O(3) bond lengths. All Sr(2)-O(1) bond lengths are 2.69 Å. Ru(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form RuO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedra are not tilted. Both Ru(1)-O(3) bond lengths are 2.03 Å. All Ru(1)-O(1) bond lengths are 1.96 Å. Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form FeO6 octahedra that share corners with four equivalent Ru(1)O6 octahedra. The corner-sharing octahedra are not tilted. Both Fe(1)-O(2) bond lengths are 2.05 Å. All Fe(1)-O(1) bond lengths are 2.00 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), one Ru(1), and one Fe(1) atom to form distorted OSr4FeRu octahedra that share corners with two equivalent O(1)Sr4FeRu octahedra, corners with six equivalent O(2)Sr5Fe octahedra, corners with six equivalent O(3)Sr5Ru octahedra, edges with two equivalent O(1)Sr4FeRu octahedra, faces with two equivalent O(2)Sr5Fe octahedra, faces with two equivalent O(3)Sr5Ru octahedra, and faces with four equivalent O(1)Sr4FeRu octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the second O site, O(2) is bonded to two equivalent Sr(2), three equivalent Sr(1), and one Fe(1) atom to form distorted OSr5Fe octahedra that share corners with five equivalent O(2)Sr5Fe octahedra, corners with twelve equivalent O(1)Sr4FeRu octahedra, edges with two equivalent O(2)Sr5Fe octahedra, edges with six equivalent O(3)Sr5Ru octahedra, and faces with four equivalent O(1)Sr4FeRu octahedra. The corner-sharing octahedral tilt angles range from 0-56°. In the third O site, O(3) is bonded to two equivalent Sr(1), three equivalent Sr(2), and one Ru(1) atom to form OSr5Ru octahedra that share corners with five equivalent O(3)Sr5Ru octahedra, corners with twelve equivalent O(1)Sr4FeRu octahedra, edges with two equivalent O(3)Sr5Ru octahedra, edges with six equivalent O(2)Sr5Fe octahedra, and faces with four equivalent O(1)Sr4FeRu octahedra. The corner-sharing octahedral tilt angles range from 0-56°.