Materials Data on KNa2Si12(BO10)3 by Materials Project
KNa2Si12(BO10)3 crystallizes in the hexagonal P6/mcc space group. The structure is three-dimensional. K1+ is bonded in a 12-coordinate geometry to twelve equivalent O2- atoms. All K–O bond lengths are 3.04 Å. Na1+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.41 Å. B3+ is bonded to four equivalent O2- atoms to form BO4 tetrahedra that share corners with four equivalent SiO4 tetrahedra. All B–O bond lengths are 1.48 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one BO4 tetrahedra and corners with three equivalent SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one B3+, and one Si4+ atom.