Materials Data on BaErAgSe3 by Materials Project
BaErAgSe3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ba2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Ba–Se bond distances ranging from 3.27–3.59 Å. Er3+ is bonded to six Se2- atoms to form ErSe6 octahedra that share corners with two equivalent ErSe6 octahedra, edges with two equivalent ErSe6 octahedra, and edges with four equivalent AgSe4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are two shorter (2.91 Å) and four longer (2.94 Å) Er–Se bond lengths. Ag1+ is bonded to four Se2- atoms to form AgSe4 tetrahedra that share corners with two equivalent AgSe4 tetrahedra and edges with four equivalent ErSe6 octahedra. There are two shorter (2.63 Å) and two longer (2.67 Å) Ag–Se bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent Ba2+, two equivalent Er3+, and one Ag1+ atom. In the second Se2- site, Se2- is bonded to two equivalent Ba2+, two equivalent Er3+, and two equivalent Ag1+ atoms to form a mixture of distorted corner and edge-sharing SeBa2Er2Ag2 octahedra. The corner-sharing octahedral tilt angles are 0°.