CaSi2 is alpha boron-derived structured and crystallizes in the trigonal R-3m space group. Ca(1) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a 7-coordinate geometry to four equivalent Ca(1) and three equivalent Si(2) atoms. In the second Si site, Si(1) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Si(1) atoms.
CaSi2 is alpha boron-derived structured and crystallizes in the trigonal R-3m space group. Ca(1) is bonded in a 7-coordinate geometry to three equivalent Si(1) and four equivalent Si(2) atoms. All Ca(1)-Si(1) bond lengths are 3.02 Å. All Ca(1)-Si(2) bond lengths are 3.11 Å. There are two inequivalent Si sites. In the first Si site, Si(2) is bonded in a 7-coordinate geometry to four equivalent Ca(1) and three equivalent Si(2) atoms. All Si(2)-Si(2) bond lengths are 2.43 Å. In the second Si site, Si(1) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Si(1) atoms. All Si(1)-Si(1) bond lengths are 2.37 Å.