Materials Data on ErAgSe2 by Materials Project

AgErSe2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Er3+ is bonded to six Se2- atoms to form ErSe6 octahedra that share corners with six equivalent ErSe6 octahedra, edges with four equivalent ErSe6 octahedra, and edges with eight equivalent AgSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.84 Å) and four longer (2.89 Å) Er–Se bond lengths. Ag1+ is bonded to six Se2- atoms to form AgSe6 octahedra that share corners with six equivalent AgSe6 octahedra, edges with four equivalent AgSe6 octahedra, and edges with eight equivalent ErSe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.84 Å) and four longer (2.89 Å) Ag–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four equivalent Er3+ and two equivalent Ag1+ atoms to form a mixture of corner and edge-sharing SeEr4Ag2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second Se2- site, Se2- is bonded to two equivalent Er3+ and four equivalent Ag1+ atoms to form SeEr2Ag4 octahedra that share corners with six equivalent SeEr2Ag4 octahedra and edges with twelve SeEr4Ag2 octahedra. The corner-sharing octahedral tilt angles are 0°.