Materials Data on KTi3Si2P6O25 by Materials Project
KTi3P6Si2O25 crystallizes in the trigonal P-31c space group. The structure is three-dimensional. K1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All K–O bond lengths are 3.13 Å. There are two inequivalent Ti+3.67+ sites. In the first Ti+3.67+ site, Ti+3.67+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six equivalent PO4 tetrahedra. There is three shorter (1.99 Å) and three longer (2.00 Å) Ti–O bond length. In the second Ti+3.67+ site, Ti+3.67+ is bonded to six equivalent O2- atoms to form TiO6 octahedra that share corners with six equivalent PO4 tetrahedra. All Ti–O bond lengths are 1.97 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with three equivalent PO4 tetrahedra. There is one shorter (1.60 Å) and three longer (1.63 Å) Si–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three TiO6 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 26–39°. There are a spread of P–O bond distances ranging from 1.52–1.60 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti+3.67+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Ti+3.67+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Ti+3.67+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Si4+ and one P5+ atom.