Ca10Si6F crystallizes in the tetragonal I-42m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a single-bond geometry to two equivalent Si(1), three equivalent Si(2), and one F(1) atom. In the second Ca site, Ca(2) is bonded to two equivalent Si(1) and three equivalent Si(2) atoms to form a mixture of distorted edge and corner-sharing CaSi5 trigonal bipyramids. In the third Ca site, Ca(3) is bonded in a rectangular see-saw-like geometry to four equivalent Si(2) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to four equivalent Ca(1) and four equivalent Ca(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ca(3), three equivalent Ca(1), three equivalent Ca(2), and one Si(2) atom. F(1) is bonded in a tetrahedral geometry to four equivalent Ca(1) atoms.
Ca10Si6F crystallizes in the tetragonal I-42m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a single-bond geometry to two equivalent Si(1), three equivalent Si(2), and one F(1) atom. Both Ca(1)-Si(1) bond lengths are 3.21 Å. There are two shorter (3.11 Å) and one longer (3.21 Å) Ca(1)-Si(2) bond length. The Ca(1)-F(1) bond length is 2.34 Å. In the second Ca site, Ca(2) is bonded to two equivalent Si(1) and three equivalent Si(2) atoms to form a mixture of distorted edge and corner-sharing CaSi5 trigonal bipyramids. Both Ca(2)-Si(1) bond lengths are 3.23 Å. There are two shorter (3.05 Å) and one longer (3.08 Å) Ca(2)-Si(2) bond length. In the third Ca site, Ca(3) is bonded in a rectangular see-saw-like geometry to four equivalent Si(2) atoms. All Ca(3)-Si(2) bond lengths are 3.09 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to four equivalent Ca(1) and four equivalent Ca(2) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Ca(3), three equivalent Ca(1), three equivalent Ca(2), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.41 Å. F(1) is bonded in a tetrahedral geometry to four equivalent Ca(1) atoms.