Ca3Fe2(RhO6)2 crystallizes in the trigonal R32 space group. Ca(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to six equivalent O(2) atoms to form distorted FeO6 pentagonal pyramids that share faces with two equivalent Rh(1)O6 octahedra. In the second Fe site, Fe(2) is bonded to six equivalent O(1) atoms to form distorted FeO6 pentagonal pyramids that share faces with two equivalent Rh(1)O6 octahedra. Rh(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form RhO6 octahedra that share  a faceface with one Fe(1)O6 pentagonal pyramid and  a faceface with one Fe(2)O6 pentagonal pyramid. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Ca(1), one Fe(2), and one Rh(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Fe(1), and one Rh(1) atom.
Ca3Fe2(RhO6)2 crystallizes in the trigonal R32 space group. Ca(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. There are two shorter (2.37 Å) and two longer (2.53 Å) Ca(1)-O(1) bond lengths. There are two shorter (2.53 Å) and two longer (2.59 Å) Ca(1)-O(2) bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to six equivalent O(2) atoms to form distorted FeO6 pentagonal pyramids that share faces with two equivalent Rh(1)O6 octahedra. All Fe(1)-O(2) bond lengths are 1.96 Å. In the second Fe site, Fe(2) is bonded to six equivalent O(1) atoms to form distorted FeO6 pentagonal pyramids that share faces with two equivalent Rh(1)O6 octahedra. All Fe(2)-O(1) bond lengths are 2.08 Å. Rh(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form RhO6 octahedra that share  a faceface with one Fe(1)O6 pentagonal pyramid and  a faceface with one Fe(2)O6 pentagonal pyramid. All Rh(1)-O(1) bond lengths are 1.96 Å. All Rh(1)-O(2) bond lengths are 1.99 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Ca(1), one Fe(2), and one Rh(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca(1), one Fe(1), and one Rh(1) atom.