DOI: 10.17188/1705699
title: Materials Data on Ba4Cu2Si21 by Materials Project

description: Ba4Cu2Si21 crystallizes in the orthorhombic Ama2 space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to twenty Si+0.57- atoms. There are a spread of Ba–Si bond distances ranging from 3.29–3.51 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Si+0.57- atoms. There are a spread of Ba–Si bond distances ranging from 3.38–3.60 Å. In the third Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Si+0.57- atoms. There are a spread of Ba–Si bond distances ranging from 3.40–3.59 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Si+0.57- atoms. There are a spread of Ba–Si bond distances ranging from 3.38–3.61 Å. There are two inequivalent Cu2+ sites. In the first Cu2+ site, Cu2+ is bonded in a tetrahedral geometry to four Si+0.57- atoms. All Cu–Si bond lengths are 2.39 Å. In the second Cu2+ site, Cu2+ is bonded in a tetrahedral geometry to four Si+0.57- atoms. There are two shorter (2.35 Å) and two longer (2.36 Å) Cu–Si bond lengths. There are thirteen inequivalent Si+0.57- sites. In the first Si+0.57- site, Si+0.57- is bonded in a distorted tetrahedral geometry to four Si+0.57- atoms. There are a spread of Si–Si bond distances ranging from 2.43–2.46 Å. In the second Si+0.57- site, Si+0.57- is bonded in a 8-coordinate geometry to three Ba2+, one Cu2+, and three Si+0.57- atoms. There are two shorter (2.40 Å) and one longer (2.49 Å) Si–Si bond lengths. In the third Si+0.57- site, Si+0.57- is bonded in a 7-coordinate geometry to three Ba2+ and four Si+0.57- atoms. There are two shorter (2.41 Å) and one longer (2.52 Å) Si–Si bond lengths. In the fourth Si+0.57- site, Si+0.57- is bonded in a 5-coordinate geometry to one Ba2+ and four Si+0.57- atoms. There are a spread of Si–Si bond distances ranging from 2.36–2.42 Å. In the fifth Si+0.57- site, Si+0.57- is bonded in a 8-coordinate geometry to one Ba2+ and four Si+0.57- atoms. There are a spread of Si–Si bond distances ranging from 2.38–2.42 Å. In the sixth Si+0.57- site, Si+0.57- is bonded in a 8-coordinate geometry to one Ba2+ and four Si+0.57- atoms. There are a spread of Si–Si bond distances ranging from 2.37–2.42 Å. In the seventh Si+0.57- site, Si+0.57- is bonded in a 8-coordinate geometry to one Ba2+ and four Si+0.57- atoms. Both Si–Si bond lengths are 2.42 Å. In the eighth Si+0.57- site, Si+0.57- is bonded in a 7-coordinate geometry to three Ba2+, one Cu2+, and three Si+0.57- atoms. The Si–Si bond length is 2.47 Å. In the ninth Si+0.57- site, Si+0.57- is bonded in a 7-coordinate geometry to three Ba2+ and four Si+0.57- atoms. The Si–Si bond length is 2.48 Å. In the tenth Si+0.57- site, Si+0.57- is bonded in a 7-coordinate geometry to three Ba2+ and four Si+0.57- atoms. In the eleventh Si+0.57- site, Si+0.57- is bonded in a 7-coordinate geometry to three Ba2+, one Cu2+, and three Si+0.57- atoms. The Si–Si bond length is 2.50 Å. In the twelfth Si+0.57- site, Si+0.57- is bonded in a 8-coordinate geometry to three Ba2+, one Cu2+, and three Si+0.57- atoms. In the thirteenth Si+0.57- site, Si+0.57- is bonded in a 8-coordinate geometry to three Ba2+, one Cu2+, and three Si+0.57- atoms.