DOE OSTI2020
(Be3Al2Si6O18)8O2 crystallizes in the orthorhombic I222 space group. The structure is three-dimensional and consists of two water molecules and one Be3Al2Si6O18 framework. In the Be3Al2Si6O18 framework, there are four inequivalent Be sites. In the first Be site, 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 1.67 Å. In the second Be site, 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 1.67 Å. In the third Be site, Be is bonded to four O atoms to form distorted BeO4 trigonal pyramids that share corners with four SiO4 tetrahedra and edges with two AlO6 octahedra. All Be–O bond lengths are 1.67 Å. In the fourth Be site, Be is bonded to four O atoms to form distorted BeO4 trigonal pyramids that share corners with four SiO4 tetrahedra and edges with two equivalent AlO6 octahedra. All Be–O bond lengths are 1.67 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra and edges with three BeO4 trigonal pyramids. All Al–O bond lengths are 1.93 Å. In the second Al site, Al is bonded to six equivalent O atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra and edges with three BeO4 trigonal pyramids. All Al–O bond lengths are 1.93 Å. In the third Al site, Al is bonded to six O atoms to form AlO6 octahedra that share corners with six SiO4 tetrahedra and edges with three BeO4 trigonal pyramids. All Al–O bond lengths are 1.93 Å. There are two inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO6 octahedra, corners with two equivalent SiO4 tetrahedra, and corners with two equivalent BeO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 44°. There is two shorter (1.61 Å) and two longer (1.64 Å) Si–O bond length. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two AlO6 octahedra, corners with two equivalent SiO4 tetrahedra, and corners with two equivalent BeO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 44°. There is two shorter (1.61 Å) and two longer (1.64 Å) Si–O bond length. There are nine inequivalent O sites. In the first O site, O is bonded in a linear geometry to two equivalent Si atoms. In the second O site, O is bonded in a linear geometry to two equivalent Si atoms. In the third O site, O is bonded in a distorted trigonal planar geometry to one Be, one Al, and one Si atom. In the fourth O site, O is bonded in a distorted trigonal planar geometry to one Be, one Al, and one Si atom. The O–Si bond length is 1.64 Å. In the fifth O site, O is bonded in a distorted trigonal planar geometry to one Be, one Al, and one Si atom. In the sixth O site, O is bonded in a distorted trigonal planar geometry to one Be, one Al, and one Si atom. The O–Si bond length is 1.64 Å. In the seventh O site, O is bonded in a distorted trigonal planar geometry to one Be, one Al, and one Si atom. The O–Si bond length is 1.64 Å. In the eighth O site, O is bonded in a linear geometry to two equivalent Si atoms. In the ninth O site, O is bonded in a linear geometry to two equivalent Si atoms. Both O–Si bond lengths are 1.61 Å.