Rb3OI is (Cubic) Perovskite-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a linear geometry to one O(1), one O(2), one I(2), and three equivalent I(1) atoms. In the second Rb site, Rb(2) is bonded in a distorted L-shaped geometry to two equivalent O(1), two equivalent I(1), and two equivalent I(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Rb(1) and three equivalent Rb(2) atoms to form ORb6 octahedra that share corners with three equivalent I(1)Rb12 cuboctahedra, corners with three equivalent O(2)Rb6 octahedra, faces with three equivalent I(2)Rb12 cuboctahedra, faces with four equivalent I(1)Rb12 cuboctahedra, and  a faceface with one O(1)Rb6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded to six equivalent Rb(1) atoms to form ORb6 octahedra that share corners with six equivalent O(1)Rb6 octahedra, faces with two equivalent I(2)Rb12 cuboctahedra, and faces with six equivalent I(1)Rb12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There are two inequivalent I sites. In the first I site, I(1) is bonded to three equivalent Rb(2) and nine equivalent Rb(1) atoms to form IRb12 cuboctahedra that share corners with three equivalent I(2)Rb12 cuboctahedra, corners with six equivalent I(1)Rb12 cuboctahedra, corners with three equivalent O(1)Rb6 octahedra, faces with three equivalent I(2)Rb12 cuboctahedra, faces with four equivalent I(1)Rb12 cuboctahedra, faces with three equivalent O(2)Rb6 octahedra, and faces with four equivalent O(1)Rb6 octahedra. The corner-sharing octahedral tilt angles are 10°. In the second I site, I(2) is bonded to six equivalent Rb(1) and six equivalent Rb(2) atoms to form IRb12 cuboctahedra that share corners with six equivalent I(1)Rb12 cuboctahedra, corners with six equivalent I(2)Rb12 cuboctahedra, faces with six equivalent I(1)Rb12 cuboctahedra, faces with two equivalent O(2)Rb6 octahedra, and faces with six equivalent O(1)Rb6 octahedra.
Rb3OI is (Cubic) Perovskite-like structured and crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a linear geometry to one O(1), one O(2), one I(2), and three equivalent I(1) atoms. The Rb(1)-O(1) bond length is 2.76 Å. The Rb(1)-O(2) bond length is 2.78 Å. The Rb(1)-I(2) bond length is 4.03 Å. There are two shorter (3.95 Å) and one longer (4.04 Å) Rb(1)-I(1) bond length. In the second Rb site, Rb(2) is bonded in a distorted L-shaped geometry to two equivalent O(1), two equivalent I(1), and two equivalent I(2) atoms. Both Rb(2)-O(1) bond lengths are 2.71 Å. Both Rb(2)-I(1) bond lengths are 4.08 Å. Both Rb(2)-I(2) bond lengths are 3.96 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to three equivalent Rb(1) and three equivalent Rb(2) atoms to form ORb6 octahedra that share corners with three equivalent I(1)Rb12 cuboctahedra, corners with three equivalent O(2)Rb6 octahedra, faces with three equivalent I(2)Rb12 cuboctahedra, faces with four equivalent I(1)Rb12 cuboctahedra, and  a faceface with one O(1)Rb6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second O site, O(2) is bonded to six equivalent Rb(1) atoms to form ORb6 octahedra that share corners with six equivalent O(1)Rb6 octahedra, faces with two equivalent I(2)Rb12 cuboctahedra, and faces with six equivalent I(1)Rb12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There are two inequivalent I sites. In the first I site, I(1) is bonded to three equivalent Rb(2) and nine equivalent Rb(1) atoms to form IRb12 cuboctahedra that share corners with three equivalent I(2)Rb12 cuboctahedra, corners with six equivalent I(1)Rb12 cuboctahedra, corners with three equivalent O(1)Rb6 octahedra, faces with three equivalent I(2)Rb12 cuboctahedra, faces with four equivalent I(1)Rb12 cuboctahedra, faces with three equivalent O(2)Rb6 octahedra, and faces with four equivalent O(1)Rb6 octahedra. The corner-sharing octahedral tilt angles are 10°. In the second I site, I(2) is bonded to six equivalent Rb(1) and six equivalent Rb(2) atoms to form IRb12 cuboctahedra that share corners with six equivalent I(1)Rb12 cuboctahedra, corners with six equivalent I(2)Rb12 cuboctahedra, faces with six equivalent I(1)Rb12 cuboctahedra, faces with two equivalent O(2)Rb6 octahedra, and faces with six equivalent O(1)Rb6 octahedra.