Materials Data on CdI2 by Materials Project
CdI2 is trigonal omega-like structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of five CdI2 sheets oriented in the (0, 0, 1) direction. In one of the CdI2 sheets, there are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to six I1- atoms to form a mixture of edge and corner-sharing CdI6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three shorter (3.01 Å) and three longer (3.21 Å) Cd–I bond lengths. In the second Cd2+ site, Cd2+ is bonded to six I1- atoms to form a mixture of edge and corner-sharing CdI6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three shorter (2.94 Å) and three longer (3.33 Å) Cd–I bond lengths. There are four inequivalent I1- sites. In the first I1- site, I1- is bonded in a 3-coordinate geometry to three equivalent Cd2+ and three equivalent I1- atoms. All I–I bond lengths are 3.94 Å. In the second I1- site, I1- is bonded to six Cd2+ atoms to form edge-sharing ICd6 octahedra. In the third I1- site, I1- is bonded in a distorted T-shaped geometry to three equivalent Cd2+ atoms. In the fourth I1- site, I1- is bonded in a distorted q6 geometry to nine I1- atoms. All I–I bond lengths are 4.34 Å. In four of the CdI2 sheets, Cd2+ is bonded to six I1- atoms to form edge-sharing CdI6 octahedra. There are three shorter (3.03 Å) and three longer (3.05 Å) Cd–I bond lengths. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted T-shaped geometry to three equivalent Cd2+ atoms. In the second I1- site, I1- is bonded in a distorted T-shaped geometry to three equivalent Cd2+ atoms.