Materials Data on Li2LaTa2O7 by Materials Project
Li2LaTa2O7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Li1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. All Li–O bond lengths are 2.10 Å. La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with four equivalent LaO12 cuboctahedra, faces with four equivalent LaO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are eight shorter (2.69 Å) and four longer (2.83 Å) La–O bond lengths. Ta+4.50+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five equivalent TaO6 octahedra and faces with four equivalent LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–17°. There are a spread of Ta–O bond distances ranging from 1.90–2.10 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Li1+ and one Ta+4.50+ atom to form a mixture of distorted edge and corner-sharing OLi4Ta trigonal bipyramids. In the second O2- site, O2- is bonded in a distorted linear geometry to four equivalent La3+ and two equivalent Ta+4.50+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent La3+ and two equivalent Ta+4.50+ atoms.