DOE OSTI2020
CsLi3Br4 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. Cs1+ is bonded to seven Br1- atoms to form distorted CsBr7 pentagonal bipyramids that share corners with four equivalent CsBr7 pentagonal bipyramids, corners with four equivalent LiBr4 tetrahedra, corners with four LiBr5 trigonal bipyramids, edges with two equivalent CsBr7 pentagonal bipyramids, edges with two equivalent LiBr4 tetrahedra, edges with three LiBr5 trigonal bipyramids, and faces with two equivalent CsBr7 pentagonal bipyramids. There are a spread of Cs–Br bond distances ranging from 3.56–3.81 Å. There are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four Br1- atoms to form LiBr4 tetrahedra that share corners with four equivalent CsBr7 pentagonal bipyramids, corners with two equivalent LiBr4 tetrahedra, corners with five LiBr5 trigonal bipyramids, edges with two equivalent CsBr7 pentagonal bipyramids, and an edgeedge with one LiBr5 trigonal bipyramid. There are a spread of Li–Br bond distances ranging from 2.56–2.79 Å. In the second Li1+ site, Li1+ is bonded to five Br1- atoms to form distorted LiBr5 trigonal bipyramids that share corners with two equivalent CsBr7 pentagonal bipyramids, a cornercorner with one LiBr4 tetrahedra, corners with four equivalent LiBr5 trigonal bipyramids, edges with two equivalent CsBr7 pentagonal bipyramids, an edgeedge with one LiBr4 tetrahedra, and edges with four equivalent LiBr5 trigonal bipyramids. There are a spread of Li–Br bond distances ranging from 2.53–2.94 Å. In the third Li1+ site, Li1+ is bonded to five Br1- atoms to form LiBr5 trigonal bipyramids that share corners with two equivalent CsBr7 pentagonal bipyramids, corners with four equivalent LiBr4 tetrahedra, corners with four equivalent LiBr5 trigonal bipyramids, an edgeedge with one CsBr7 pentagonal bipyramid, and edges with four equivalent LiBr5 trigonal bipyramids. There are a spread of Li–Br bond distances ranging from 2.65–2.83 Å. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a 5-coordinate geometry to two equivalent Cs1+ and three Li1+ atoms. In the second Br1- site, Br1- is bonded to five Li1+ atoms to form corner-sharing BrLi5 trigonal bipyramids. In the third Br1- site, Br1- is bonded in a 5-coordinate geometry to one Cs1+ and four Li1+ atoms. In the fourth Br1- site, Br1- is bonded in a 6-coordinate geometry to four equivalent Cs1+ and two Li1+ atoms.