CsPbI3 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 9-coordinate geometry to two equivalent I(2), three equivalent I(1), and four equivalent I(3) atoms. Pb(1) is bonded to one I(3), two equivalent I(1), and three equivalent I(2) atoms to form edge-sharing PbI6 octahedra. There are three inequivalent I sites. In the first I site, I(1) is bonded to three equivalent Cs(1) and two equivalent Pb(1) atoms to form distorted ICs3Pb2 trigonal bipyramids that share corners with six equivalent I(3)Cs4Pb square pyramids, corners with six equivalent I(2)Cs2Pb3 trigonal bipyramids, edges with four equivalent I(3)Cs4Pb square pyramids, edges with three equivalent I(2)Cs2Pb3 trigonal bipyramids, and edges with four equivalent I(1)Cs3Pb2 trigonal bipyramids. In the second I site, I(2) is bonded to two equivalent Cs(1) and three equivalent Pb(1) atoms to form ICs2Pb3 trigonal bipyramids that share corners with three equivalent I(3)Cs4Pb square pyramids, corners with four equivalent I(2)Cs2Pb3 trigonal bipyramids, corners with six equivalent I(1)Cs3Pb2 trigonal bipyramids, edges with four equivalent I(3)Cs4Pb square pyramids, edges with two equivalent I(2)Cs2Pb3 trigonal bipyramids, and edges with three equivalent I(1)Cs3Pb2 trigonal bipyramids. In the third I site, I(3) is bonded to four equivalent Cs(1) and one Pb(1) atom to form distorted ICs4Pb square pyramids that share corners with four equivalent I(3)Cs4Pb square pyramids, corners with three equivalent I(2)Cs2Pb3 trigonal bipyramids, corners with six equivalent I(1)Cs3Pb2 trigonal bipyramids, edges with four equivalent I(3)Cs4Pb square pyramids, edges with four equivalent I(2)Cs2Pb3 trigonal bipyramids, and edges with four equivalent I(1)Cs3Pb2 trigonal bipyramids.
CsPbI3 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 9-coordinate geometry to two equivalent I(2), three equivalent I(1), and four equivalent I(3) atoms. There is one shorter (4.06 Å) and one longer (4.29 Å) Cs(1)-I(2) bond length. There are two shorter (4.00 Å) and one longer (4.08 Å) Cs(1)-I(1) bond length. There are two shorter (3.93 Å) and two longer (3.95 Å) Cs(1)-I(3) bond lengths. Pb(1) is bonded to one I(3), two equivalent I(1), and three equivalent I(2) atoms to form edge-sharing PbI6 octahedra. The Pb(1)-I(3) bond length is 3.09 Å. Both Pb(1)-I(1) bond lengths are 3.26 Å. There are two shorter (3.30 Å) and one longer (3.43 Å) Pb(1)-I(2) bond length. There are three inequivalent I sites. In the first I site, I(1) is bonded to three equivalent Cs(1) and two equivalent Pb(1) atoms to form distorted ICs3Pb2 trigonal bipyramids that share corners with six equivalent I(3)Cs4Pb square pyramids, corners with six equivalent I(2)Cs2Pb3 trigonal bipyramids, edges with four equivalent I(3)Cs4Pb square pyramids, edges with three equivalent I(2)Cs2Pb3 trigonal bipyramids, and edges with four equivalent I(1)Cs3Pb2 trigonal bipyramids. In the second I site, I(2) is bonded to two equivalent Cs(1) and three equivalent Pb(1) atoms to form ICs2Pb3 trigonal bipyramids that share corners with three equivalent I(3)Cs4Pb square pyramids, corners with four equivalent I(2)Cs2Pb3 trigonal bipyramids, corners with six equivalent I(1)Cs3Pb2 trigonal bipyramids, edges with four equivalent I(3)Cs4Pb square pyramids, edges with two equivalent I(2)Cs2Pb3 trigonal bipyramids, and edges with three equivalent I(1)Cs3Pb2 trigonal bipyramids. In the third I site, I(3) is bonded to four equivalent Cs(1) and one Pb(1) atom to form distorted ICs4Pb square pyramids that share corners with four equivalent I(3)Cs4Pb square pyramids, corners with three equivalent I(2)Cs2Pb3 trigonal bipyramids, corners with six equivalent I(1)Cs3Pb2 trigonal bipyramids, edges with four equivalent I(3)Cs4Pb square pyramids, edges with four equivalent I(2)Cs2Pb3 trigonal bipyramids, and edges with four equivalent I(1)Cs3Pb2 trigonal bipyramids.