Materials Data on Li2MgBr4 by Materials Project
Li2MgBr4 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Li1+ is bonded to six Br1- atoms to form LiBr6 octahedra that share corners with six equivalent LiBr6 octahedra, edges with four equivalent LiBr6 octahedra, and edges with four equivalent MgBr6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are four shorter (2.77 Å) and two longer (2.79 Å) Li–Br bond lengths. Mg2+ is bonded to six Br1- atoms to form MgBr6 octahedra that share edges with two equivalent MgBr6 octahedra and edges with eight equivalent LiBr6 octahedra. There are two shorter (2.69 Å) and four longer (2.70 Å) Mg–Br bond lengths. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded to four equivalent Li1+ and one Mg2+ atom to form a mixture of corner and edge-sharing BrLi4Mg square pyramids. In the second Br1- site, Br1- is bonded in a rectangular see-saw-like geometry to two equivalent Li1+ and two equivalent Mg2+ atoms.