Cs3Bi2Cl9 crystallizes in the trigonal P321 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to six equivalent Cl(1) and six equivalent Cl(2) atoms to form CsCl12 cuboctahedra that share corners with six equivalent Cs(1)Cl12 cuboctahedra, corners with six equivalent Cs(2)Cl12 cuboctahedra, faces with six equivalent Cs(2)Cl12 cuboctahedra, and faces with six equivalent Bi(1)Cl6 octahedra. In the second Cs site, Cs(2) is bonded to three equivalent Cl(1) and nine equivalent Cl(2) atoms to form CsCl12 cuboctahedra that share corners with three equivalent Cs(1)Cl12 cuboctahedra, corners with nine equivalent Cs(2)Cl12 cuboctahedra, faces with three equivalent Cs(1)Cl12 cuboctahedra, faces with three equivalent Cs(2)Cl12 cuboctahedra, and faces with five equivalent Bi(1)Cl6 octahedra. Bi(1) is bonded to three equivalent Cl(1) and three equivalent Cl(2) atoms to form BiCl6 octahedra that share corners with three equivalent Bi(1)Cl6 octahedra, faces with three equivalent Cs(1)Cl12 cuboctahedra, and faces with five equivalent Cs(2)Cl12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Bi(1) atoms to form distorted ClCs4Bi2 octahedra that share corners with six equivalent Cl(1)Cs4Bi2 octahedra, corners with sixteen equivalent Cl(2)Cs4Bi square pyramids, edges with four equivalent Cl(2)Cs4Bi square pyramids, faces with four equivalent Cl(1)Cs4Bi2 octahedra, and faces with four equivalent Cl(2)Cs4Bi square pyramids. The corner-sharing octahedral tilt angles range from 0-60°. In the second Cl site, Cl(2) is bonded to one Cs(1), three equivalent Cs(2), and one Bi(1) atom to form distorted ClCs4Bi square pyramids that share corners with eight equivalent Cl(1)Cs4Bi2 octahedra, corners with thirteen equivalent Cl(2)Cs4Bi square pyramids, edges with two equivalent Cl(1)Cs4Bi2 octahedra, edges with six equivalent Cl(2)Cs4Bi square pyramids, faces with two equivalent Cl(1)Cs4Bi2 octahedra, and faces with two equivalent Cl(2)Cs4Bi square pyramids. The corner-sharing octahedral tilt angles range from 1-63°.
Cs3Bi2Cl9 crystallizes in the trigonal P321 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded to six equivalent Cl(1) and six equivalent Cl(2) atoms to form CsCl12 cuboctahedra that share corners with six equivalent Cs(1)Cl12 cuboctahedra, corners with six equivalent Cs(2)Cl12 cuboctahedra, faces with six equivalent Cs(2)Cl12 cuboctahedra, and faces with six equivalent Bi(1)Cl6 octahedra. There are three shorter (3.71 Å) and three longer (3.98 Å) Cs(1)-Cl(1) bond lengths. All Cs(1)-Cl(2) bond lengths are 3.91 Å. In the second Cs site, Cs(2) is bonded to three equivalent Cl(1) and nine equivalent Cl(2) atoms to form CsCl12 cuboctahedra that share corners with three equivalent Cs(1)Cl12 cuboctahedra, corners with nine equivalent Cs(2)Cl12 cuboctahedra, faces with three equivalent Cs(1)Cl12 cuboctahedra, faces with three equivalent Cs(2)Cl12 cuboctahedra, and faces with five equivalent Bi(1)Cl6 octahedra. All Cs(2)-Cl(1) bond lengths are 3.93 Å. There are a spread of Cs(2)-Cl(2) bond distances ranging from 3.77-3.91 Å. Bi(1) is bonded to three equivalent Cl(1) and three equivalent Cl(2) atoms to form BiCl6 octahedra that share corners with three equivalent Bi(1)Cl6 octahedra, faces with three equivalent Cs(1)Cl12 cuboctahedra, and faces with five equivalent Cs(2)Cl12 cuboctahedra. The corner-sharing octahedral tilt angles are 5°. All Bi(1)-Cl(1) bond lengths are 2.84 Å. All Bi(1)-Cl(2) bond lengths are 2.59 Å. There are two inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Bi(1) atoms to form distorted ClCs4Bi2 octahedra that share corners with six equivalent Cl(1)Cs4Bi2 octahedra, corners with sixteen equivalent Cl(2)Cs4Bi square pyramids, edges with four equivalent Cl(2)Cs4Bi square pyramids, faces with four equivalent Cl(1)Cs4Bi2 octahedra, and faces with four equivalent Cl(2)Cs4Bi square pyramids. The corner-sharing octahedral tilt angles range from 0-60°. In the second Cl site, Cl(2) is bonded to one Cs(1), three equivalent Cs(2), and one Bi(1) atom to form distorted ClCs4Bi square pyramids that share corners with eight equivalent Cl(1)Cs4Bi2 octahedra, corners with thirteen equivalent Cl(2)Cs4Bi square pyramids, edges with two equivalent Cl(1)Cs4Bi2 octahedra, edges with six equivalent Cl(2)Cs4Bi square pyramids, faces with two equivalent Cl(1)Cs4Bi2 octahedra, and faces with two equivalent Cl(2)Cs4Bi square pyramids. The corner-sharing octahedral tilt angles range from 1-63°.