Materials Data on SrLi2Ta2O7 by Materials Project
Li2SrTa2O7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Li1+ is bonded to five O2- atoms to form distorted LiO5 trigonal bipyramids that share corners with two equivalent SrO12 cuboctahedra, corners with two equivalent TaO6 octahedra, corners with four equivalent LiO5 trigonal bipyramids, edges with two equivalent TaO6 octahedra, and edges with four equivalent LiO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 66°. There are a spread of Li–O bond distances ranging from 2.05–2.38 Å. Sr2+ is bonded to twelve O2- atoms to form distorted SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, corners with four equivalent LiO5 trigonal bipyramids, faces with four equivalent SrO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.60–3.04 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five equivalent TaO6 octahedra, corners with two equivalent LiO5 trigonal bipyramids, edges with two equivalent LiO5 trigonal bipyramids, and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–19°. There are a spread of Ta–O bond distances ranging from 1.89–2.12 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded to four equivalent Li1+ and one Ta5+ atom to form a mixture of distorted edge and corner-sharing OLi4Ta trigonal bipyramids. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, two equivalent Sr2+, and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Sr2+ and two equivalent Ta5+ atoms.