Materials Data on K6Ti2O7 by Materials Project
K6Ti2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to five O2- atoms to form distorted KO5 trigonal bipyramids that share corners with three equivalent TiO4 tetrahedra, an edgeedge with one TiO4 tetrahedra, and edges with two equivalent KO5 trigonal bipyramids. There are a spread of K–O bond distances ranging from 2.69–2.98 Å. In the second K1+ site, K1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of K–O bond distances ranging from 2.69–3.18 Å. In the third K1+ site, K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 2.72–3.21 Å. Ti4+ is bonded to four O2- atoms to form TiO4 tetrahedra that share a cornercorner with one TiO4 tetrahedra, corners with three equivalent KO5 trigonal bipyramids, and an edgeedge with one KO5 trigonal bipyramid. There is three shorter (1.82 Å) and one longer (1.91 Å) Ti–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four K1+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four K1+ and one Ti4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to five K1+ and one Ti4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to five K1+ and one Ti4+ atom.