Materials Data on Sr3CaSi8 by Materials Project

Sr3CaSi8 crystallizes in the trigonal R32 space group. The structure is three-dimensional. Sr2+ is bonded in a 8-coordinate geometry to eight Si1- atoms. There are a spread of Sr–Si bond distances ranging from 3.22–3.37 Å. Ca2+ is bonded in a distorted body-centered cubic geometry to eight Si1- atoms. There are six shorter (3.21 Å) and two longer (3.35 Å) Ca–Si bond lengths. There are two inequivalent Si1- sites. In the first Si1- site, Si1- is bonded in a 7-coordinate geometry to three equivalent Sr2+, one Ca2+, and three equivalent Si1- atoms. All Si–Si bond lengths are 2.40 Å. In the second Si1- site, Si1- is bonded in a 7-coordinate geometry to three equivalent Sr2+, one Ca2+, and three Si1- atoms. There are one shorter (2.37 Å) and one longer (2.38 Å) Si–Si bond lengths.