CaSi3 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 12-coordinate geometry to four equivalent Si(1) and eight equivalent Si(2) atoms. In the second Ca site, Ca(2) is bonded in a 12-coordinate geometry to four equivalent Si(1) and eight equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), one Si(1), and four equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent Si(1), and three equivalent Si(2) atoms.
CaSi3 crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 12-coordinate geometry to four equivalent Si(1) and eight equivalent Si(2) atoms. All Ca(1)-Si(1) bond lengths are 3.13 Å. There are four shorter (3.16 Å) and four longer (3.32 Å) Ca(1)-Si(2) bond lengths. In the second Ca site, Ca(2) is bonded in a 12-coordinate geometry to four equivalent Si(1) and eight equivalent Si(2) atoms. All Ca(2)-Si(1) bond lengths are 3.08 Å. All Ca(2)-Si(2) bond lengths are 3.12 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), one Si(1), and four equivalent Si(2) atoms. The Si(1)-Si(1) bond length is 2.39 Å. All Si(1)-Si(2) bond lengths are 2.58 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), two equivalent Si(1), and three equivalent Si(2) atoms. There is one shorter (2.37 Å) and two longer (2.69 Å) Si(2)-Si(2) bond lengths.