DOE OSTI2020
Cs2AgBr3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to seven Br1- atoms to form distorted CsBr7 pentagonal bipyramids that share corners with six CsBr7 pentagonal bipyramids, a cornercorner with one AgBr4 tetrahedra, edges with ten CsBr7 pentagonal bipyramids, and edges with four equivalent AgBr4 tetrahedra. There are a spread of Cs–Br bond distances ranging from 3.69–3.76 Å. In the second Cs1+ site, Cs1+ is bonded to seven Br1- atoms to form distorted CsBr7 pentagonal bipyramids that share corners with four equivalent CsBr7 pentagonal bipyramids, corners with three equivalent AgBr4 tetrahedra, edges with eight CsBr7 pentagonal bipyramids, edges with three equivalent AgBr4 tetrahedra, and faces with two equivalent CsBr7 pentagonal bipyramids. There are a spread of Cs–Br bond distances ranging from 3.71–3.79 Å. Ag1+ is bonded to four Br1- atoms to form AgBr4 tetrahedra that share corners with four CsBr7 pentagonal bipyramids, corners with two equivalent AgBr4 tetrahedra, and edges with seven CsBr7 pentagonal bipyramids. There are a spread of Ag–Br bond distances ranging from 2.71–2.80 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded to five Cs1+ and one Ag1+ atom to form distorted BrCs5Ag octahedra that share corners with thirteen BrCs4Ag2 octahedra, edges with seven BrCs5Ag octahedra, and faces with two BrCs4Ag2 octahedra. The corner-sharing octahedra tilt angles range from 26–62°. In the second Br1- site, Br1- is bonded to four Cs1+ and two equivalent Ag1+ atoms to form a mixture of distorted edge, corner, and face-sharing BrCs4Ag2 octahedra. The corner-sharing octahedra tilt angles range from 15–62°. In the third Br1- site, Br1- is bonded to five Cs1+ and one Ag1+ atom to form a mixture of distorted edge, corner, and face-sharing BrCs5Ag octahedra. The corner-sharing octahedra tilt angles range from 15–56°.