Materials Data on Li2Ca2Ta3O10 by Materials Project
Li2Ca2Ta3O10 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Li1+ is bonded in a 4-coordinate geometry to six O2- atoms. There are four shorter (2.09 Å) and two longer (2.80 Å) Li–O bond lengths. Ca2+ is bonded to twelve O2- atoms to form distorted CaO12 cuboctahedra that share corners with eight equivalent CaO12 cuboctahedra, faces with five equivalent CaO12 cuboctahedra, and faces with eight TaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.54–3.01 Å. There are two inequivalent Ta+4.67+ sites. In the first Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five TaO6 octahedra and faces with four equivalent CaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–15°. There are a spread of Ta–O bond distances ranging from 1.90–2.11 Å. In the second Ta+4.67+ site, Ta+4.67+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with eight equivalent CaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 1.99 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Li1+, two equivalent Ca2+, and two equivalent Ta+4.67+ atoms. In the second O2- site, O2- is bonded to four equivalent Li1+ and one Ta+4.67+ atom to form a mixture of distorted corner and edge-sharing OLi4Ta trigonal bipyramids. In the third O2- site, O2- is bonded in a linear geometry to four equivalent Ca2+ and two equivalent Ta+4.67+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ca2+ and two Ta+4.67+ atoms.