Ca2PI is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. Ca(1) is bonded to three equivalent P(1) and three equivalent I(1) atoms to form a mixture of edge and corner-sharing CaP3I3 octahedra. The corner-sharing octahedra are not tilted. P(1) is bonded to six equivalent Ca(1) atoms to form PCa6 octahedra that share corners with six equivalent I(1)Ca6 octahedra, edges with six equivalent P(1)Ca6 octahedra, and edges with six equivalent I(1)Ca6 octahedra. The corner-sharing octahedral tilt angles are 13°. I(1) is bonded to six equivalent Ca(1) atoms to form ICa6 octahedra that share corners with six equivalent P(1)Ca6 octahedra, edges with six equivalent P(1)Ca6 octahedra, and edges with six equivalent I(1)Ca6 octahedra. The corner-sharing octahedral tilt angles are 13°.
Ca2PI is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. Ca(1) is bonded to three equivalent P(1) and three equivalent I(1) atoms to form a mixture of edge and corner-sharing CaP3I3 octahedra. The corner-sharing octahedra are not tilted. All Ca(1)-P(1) bond lengths are 2.86 Å. All Ca(1)-I(1) bond lengths are 3.39 Å. P(1) is bonded to six equivalent Ca(1) atoms to form PCa6 octahedra that share corners with six equivalent I(1)Ca6 octahedra, edges with six equivalent P(1)Ca6 octahedra, and edges with six equivalent I(1)Ca6 octahedra. The corner-sharing octahedral tilt angles are 13°. I(1) is bonded to six equivalent Ca(1) atoms to form ICa6 octahedra that share corners with six equivalent P(1)Ca6 octahedra, edges with six equivalent P(1)Ca6 octahedra, and edges with six equivalent I(1)Ca6 octahedra. The corner-sharing octahedral tilt angles are 13°.