DOE OSTI2020
Li3Ti3(PO4)4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to five O2- atoms to form distorted LiO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one LiO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 57°. There are a spread of Li–O bond distances ranging from 1.87–2.25 Å. In the second Li1+ site, Li1+ is bonded to five O2- atoms to form distorted LiO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one TiO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 58°. There are a spread of Li–O bond distances ranging from 1.94–2.17 Å. In the third Li1+ site, Li1+ is bonded to five O2- atoms to form distorted LiO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one LiO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 59°. There are a spread of Li–O bond distances ranging from 1.87–2.23 Å. There are three inequivalent Ti3+ sites. In the first Ti3+ site, Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra, corners with two LiO5 trigonal bipyramids, an edgeedge with one LiO5 trigonal bipyramid, and an edgeedge with one TiO5 trigonal bipyramid. There are a spread of Ti–O bond distances ranging from 2.02–2.24 Å. In the second Ti3+ site, Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six PO4 tetrahedra, a cornercorner with one LiO5 trigonal bipyramid, a cornercorner with one TiO5 trigonal bipyramid, and edges with two LiO5 trigonal bipyramids. There are a spread of Ti–O bond distances ranging from 1.96–2.28 Å. In the third Ti3+ site, Ti3+ is bonded to five O2- atoms to form TiO5 trigonal bipyramids that share a cornercorner with one TiO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one TiO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one LiO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 55°. There are a spread of Ti–O bond distances ranging from 1.95–2.09 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three TiO6 octahedra, a cornercorner with one LiO5 trigonal bipyramid, corners with two equivalent TiO5 trigonal bipyramids, and an edgeedge with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 31–50°. There is three shorter (1.54 Å) and one longer (1.59 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three TiO6 octahedra, corners with three LiO5 trigonal bipyramids, and an edgeedge with one TiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 34–52°. There are a spread of P–O bond distances ranging from 1.49–1.61 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three TiO6 octahedra, a cornercorner with one TiO5 trigonal bipyramid, corners with two LiO5 trigonal bipyramids, and an edgeedge with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 32–49°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three TiO6 octahedra, corners with three LiO5 trigonal bipyramids, and an edgeedge with one LiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 35–51°. There are a spread of P–O bond distances ranging from 1.50–1.58 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted T-shaped geometry to two Ti3+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Li1+, one Ti3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two Ti3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted T-shaped geometry to two Li1+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Li1+, one Ti3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ti3+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted T-shaped geometry to one Li1+, one Ti3+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted T-shaped geometry to one Li1+, one Ti3+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Li1+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+, one Ti3+, and one P5+ atom.