CaPbI4 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded to one I(1), one I(4), two equivalent I(2), and two equivalent I(3) atoms to form CaI6 octahedra that share corners with two equivalent Ca(1)I6 octahedra, corners with three equivalent Pb(1)I5 square pyramids,  an edgeedge with one Ca(1)I6 octahedra, and edges with two equivalent Pb(1)I5 square pyramids. The corner-sharing octahedral tilt angles are 49°. Pb(1) is bonded to one I(2), one I(3), one I(4), and two equivalent I(1) atoms to form distorted PbI5 square pyramids that share corners with three equivalent Ca(1)I6 octahedra, corners with two equivalent Pb(1)I5 square pyramids, and edges with two equivalent Ca(1)I6 octahedra. The corner-sharing octahedral tilt angles range from 51-81°. There are four inequivalent I sites. In the first I site, I(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Pb(1) atoms. In the second I site, I(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Pb(1) atom. In the third I site, I(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one Pb(1) atom. In the fourth I site, I(4) is bonded in an L-shaped geometry to one Ca(1) and one Pb(1) atom.
CaPbI4 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded to one I(1), one I(4), two equivalent I(2), and two equivalent I(3) atoms to form CaI6 octahedra that share corners with two equivalent Ca(1)I6 octahedra, corners with three equivalent Pb(1)I5 square pyramids,  an edgeedge with one Ca(1)I6 octahedra, and edges with two equivalent Pb(1)I5 square pyramids. The corner-sharing octahedral tilt angles are 49°. The Ca(1)-I(1) bond length is 3.11 Å. The Ca(1)-I(4) bond length is 3.06 Å. There is one shorter (3.20 Å) and one longer (3.25 Å) Ca(1)-I(2) bond length. Both Ca(1)-I(3) bond lengths are 3.26 Å. Pb(1) is bonded to one I(2), one I(3), one I(4), and two equivalent I(1) atoms to form distorted PbI5 square pyramids that share corners with three equivalent Ca(1)I6 octahedra, corners with two equivalent Pb(1)I5 square pyramids, and edges with two equivalent Ca(1)I6 octahedra. The corner-sharing octahedral tilt angles range from 51-81°. The Pb(1)-I(2) bond length is 3.31 Å. The Pb(1)-I(3) bond length is 3.16 Å. The Pb(1)-I(4) bond length is 3.08 Å. There is one shorter (3.23 Å) and one longer (3.40 Å) Pb(1)-I(1) bond length. There are four inequivalent I sites. In the first I site, I(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Pb(1) atoms. In the second I site, I(2) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one Pb(1) atom. In the third I site, I(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one Pb(1) atom. In the fourth I site, I(4) is bonded in an L-shaped geometry to one Ca(1) and one Pb(1) atom.