Materials Data on NaBe3Al2Si6O19 by Materials Project

NaBe3Al2Si6O19 crystallizes in the hexagonal P6/mcc space group. The structure is three-dimensional. Na is bonded to eight O atoms to form NaO8 hexagonal bipyramids that share corners with two equivalent NaO8 hexagonal bipyramids and edges with six equivalent SiO4 tetrahedra. There are two shorter (2.31 Å) and six longer (2.59 Å) Na–O bond lengths. Be is bonded to four equivalent O atoms to form distorted BeO4 trigonal pyramids that share corners with four equivalent SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. All Be–O bond lengths are 1.66 Å. Al is bonded to six equivalent O atoms to form AlO6 octahedra that share corners with six equivalent SiO4 tetrahedra and edges with three equivalent BeO4 trigonal pyramids. All Al–O bond lengths are 1.93 Å. Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent AlO6 octahedra, corners with two equivalent SiO4 tetrahedra, corners with two equivalent BeO4 trigonal pyramids, and an edgeedge with one NaO8 hexagonal bipyramid. The corner-sharing octahedral tilt angles are 44°. There is two shorter (1.62 Å) and two longer (1.64 Å) Si–O bond length. There are three inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Be, one Al, and one Si atom. In the second O site, O is bonded in a distorted T-shaped geometry to one Na and two equivalent Si atoms. In the third O site, O is bonded in a linear geometry to two equivalent Na atoms.