Materials Data on Ba(AlSi)2 by Materials Project

Abstract

BaAl2Si2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ba2+ is bonded in a 7-coordinate geometry to seven Si4- atoms. There are a spread of Ba–Si bond distances ranging from 3.29–3.62 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Si4- atoms to form a mixture of corner and edge-sharing AlSi4 tetrahedra. There are three shorter (2.56 Å) and one longer (2.58 Å) Al–Si bond lengths. In the second Al3+ site, Al3+ is bonded to four Si4- atoms to form a mixture of corner and edge-sharing AlSi4 tetrahedra. There are a spread of Al–Si bond distances ranging from 2.52–2.58 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 4-coordinate geometry to four equivalent Ba2+ and four Al3+ atoms. In the second Si4- site, Si4- is bonded in a 7-coordinate geometry to three equivalent Ba2+ and four Al3+ atoms.