Sr4Re2NiO12 crystallizes in the trigonal R-3m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to three equivalent O(2) and nine equivalent O(1) atoms to form distorted SrO12 cuboctahedra that share corners with three equivalent Sr(2)O12 cuboctahedra, corners with six equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Re(1)O6 octahedra, faces with three equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(2)O12 cuboctahedra,  a faceface with one Ni(1)O6 octahedra, and faces with three equivalent Re(1)O6 octahedra. The corner-sharing octahedral tilt angles are 20°. In the second Sr site, Sr(2) is bonded to three equivalent O(1) and nine equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with three equivalent Sr(1)O12 cuboctahedra, corners with six equivalent Sr(2)O12 cuboctahedra, faces with three equivalent Sr(2)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, faces with three equivalent Ni(1)O6 octahedra, and faces with four equivalent Re(1)O6 octahedra. Re(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form ReO6 octahedra that share corners with three equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Ni(1)O6 octahedra, faces with three equivalent Sr(1)O12 cuboctahedra, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. Ni(1) is bonded to six equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Re(1)O6 octahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with six equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Sr(2), three equivalent Sr(1), and one Re(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Sr(1), three equivalent Sr(2), one Re(1), and one Ni(1) atom.
Sr4Re2NiO12 crystallizes in the trigonal R-3m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to three equivalent O(2) and nine equivalent O(1) atoms to form distorted SrO12 cuboctahedra that share corners with three equivalent Sr(2)O12 cuboctahedra, corners with six equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Re(1)O6 octahedra, faces with three equivalent Sr(1)O12 cuboctahedra, faces with four equivalent Sr(2)O12 cuboctahedra,  a faceface with one Ni(1)O6 octahedra, and faces with three equivalent Re(1)O6 octahedra. The corner-sharing octahedral tilt angles are 20°. All Sr(1)-O(2) bond lengths are 2.95 Å. There are three shorter (2.68 Å) and six longer (2.81 Å) Sr(1)-O(1) bond lengths. In the second Sr site, Sr(2) is bonded to three equivalent O(1) and nine equivalent O(2) atoms to form SrO12 cuboctahedra that share corners with three equivalent Sr(1)O12 cuboctahedra, corners with six equivalent Sr(2)O12 cuboctahedra, faces with three equivalent Sr(2)O12 cuboctahedra, faces with four equivalent Sr(1)O12 cuboctahedra, faces with three equivalent Ni(1)O6 octahedra, and faces with four equivalent Re(1)O6 octahedra. All Sr(2)-O(1) bond lengths are 2.76 Å. There are three shorter (2.78 Å) and six longer (2.80 Å) Sr(2)-O(2) bond lengths. Re(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form ReO6 octahedra that share corners with three equivalent Sr(1)O12 cuboctahedra, corners with three equivalent Ni(1)O6 octahedra, faces with three equivalent Sr(1)O12 cuboctahedra, and faces with four equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. All Re(1)-O(1) bond lengths are 1.85 Å. All Re(1)-O(2) bond lengths are 1.95 Å. Ni(1) is bonded to six equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Re(1)O6 octahedra, faces with two equivalent Sr(1)O12 cuboctahedra, and faces with six equivalent Sr(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. All Ni(1)-O(2) bond lengths are 2.05 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Sr(2), three equivalent Sr(1), and one Re(1) atom. In the second O site, O(2) is bonded in a distorted linear geometry to one Sr(1), three equivalent Sr(2), one Re(1), and one Ni(1) atom.