Materials Data on Sr4Al14O25 by Materials Project
Sr4Al14O25 crystallizes in the orthorhombic Pmma space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.48–2.88 Å. In the second Sr2+ site, Sr2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Sr–O bond distances ranging from 2.61–3.07 Å. There are six inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with eight equivalent AlO4 tetrahedra and edges with two equivalent AlO6 octahedra. There is four shorter (1.91 Å) and two longer (2.04 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent AlO4 tetrahedra and edges with four equivalent AlO6 octahedra. There is two shorter (1.89 Å) and four longer (1.95 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent AlO4 tetrahedra and edges with four AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.92–1.96 Å. In the fourth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.75–1.80 Å. In the fifth Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with five AlO6 octahedra and corners with two AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–61°. There are a spread of Al–O bond distances ranging from 1.76–1.82 Å. In the sixth Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.75–1.80 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Sr2+ and three Al3+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two Al3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+ and three Al3+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two equivalent Al3+ atoms. In the sixth O2- site, O2- is bonded to one Sr2+ and three Al3+ atoms to form distorted corner-sharing OSrAl3 trigonal pyramids. In the seventh O2- site, O2- is bonded to one Sr2+ and three Al3+ atoms to form a mixture of distorted edge and corner-sharing OSrAl3 trigonal pyramids. In the eighth O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Sr2+ and two Al3+ atoms.