DOE OSTI2020
CaGdS2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ca is bonded to six S atoms to form CaS6 octahedra that share corners with six equivalent CaS6 octahedra, edges with four equivalent CaS6 octahedra, and edges with eight equivalent GdS6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.81 Å) and two longer (2.82 Å) Ca–S bond lengths. Gd is bonded to six S atoms to form GdS6 octahedra that share corners with six equivalent GdS6 octahedra, edges with four equivalent GdS6 octahedra, and edges with eight equivalent CaS6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.81 Å) and two longer (2.82 Å) Gd–S bond lengths. There are two inequivalent S sites. In the first S site, S is bonded to two equivalent Ca and four equivalent Gd atoms to form a mixture of corner and edge-sharing SCa2Gd4 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second S site, S is bonded to four equivalent Ca and two equivalent Gd atoms to form SCa4Gd2 octahedra that share corners with six equivalent SCa4Gd2 octahedra and edges with twelve SCa2Gd4 octahedra. The corner-sharing octahedral tilt angles are 0°.