Materials Data on Li4Ca(BO3)2 by Materials Project
Li4CaB2O6 crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to four O2- atoms to form distorted LiO4 tetrahedra that share corners with three equivalent CaO6 octahedra, corners with two equivalent LiO4 tetrahedra, corners with three equivalent LiO5 trigonal bipyramids, and edges with two equivalent LiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 18–80°. There is two shorter (1.94 Å) and two longer (1.98 Å) Li–O bond length. In the second Li1+ site, Li1+ is bonded to five O2- atoms to form LiO5 trigonal bipyramids that share corners with three equivalent LiO4 tetrahedra, corners with two equivalent LiO5 trigonal bipyramids, edges with two equivalent CaO6 octahedra, edges with two equivalent LiO4 tetrahedra, and an edgeedge with one LiO5 trigonal bipyramid. There are a spread of Li–O bond distances ranging from 2.01–2.24 Å. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent LiO4 tetrahedra, edges with two equivalent CaO6 octahedra, and edges with four equivalent LiO5 trigonal bipyramids. There are four shorter (2.35 Å) and two longer (2.45 Å) Ca–O bond lengths. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.38–1.40 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three Li1+, one Ca2+, and one B3+ atom. In the second O2- site, O2- is bonded to four Li1+ and one B3+ atom to form a mixture of distorted corner and edge-sharing OLi4B trigonal bipyramids. In the third O2- site, O2- is bonded to two Li1+, two equivalent Ca2+, and one B3+ atom to form a mixture of distorted corner and edge-sharing OLi2Ca2B trigonal bipyramids.