Materials Data on Ba4Si23 by Materials Project
Ba4Si23 crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. there are two inequivalent Ba sites. In the first Ba site, Ba is bonded in a 8-coordinate geometry to twenty Si atoms. There are eight shorter (3.34 Å) and twelve longer (3.43 Å) Ba–Si bond lengths. In the second Ba site, Ba is bonded in a 12-coordinate geometry to twenty Si atoms. There are a spread of Ba–Si bond distances ranging from 3.52–3.86 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four equivalent Ba and four equivalent Si atoms to form a mixture of distorted corner and edge-sharing SiBa4Si4 tetrahedra. All Si–Si bond lengths are 2.42 Å. In the second Si site, Si is bonded in a 8-coordinate geometry to four Ba and four Si atoms. There are one shorter (2.35 Å) and three longer (2.40 Å) Si–Si bond lengths. In the third Si site, Si is bonded in a 7-coordinate geometry to three Ba and four Si atoms. The Si–Si bond length is 2.51 Å.