Ca2SiO4F crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(2), one O(4), two equivalent O(1), two equivalent O(3), and two equivalent F(1) atoms. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(2), two equivalent Ca(1), and one Si(1) atom to form distorted OCa3Si trigonal pyramids that share corners with four equivalent F(1)Ca4 tetrahedra,  an edgeedge with one F(1)Ca4 tetrahedra, and  an edgeedge with one O(1)Ca3Si trigonal pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Ca(2), and one Si(1) atom. F(1) is bonded to two equivalent Ca(1) and two equivalent Ca(2) atoms to form distorted FCa4 tetrahedra that share corners with two equivalent F(1)Ca4 tetrahedra, corners with four equivalent O(1)Ca3Si trigonal pyramids,  an edgeedge with one F(1)Ca4 tetrahedra, and  an edgeedge with one O(1)Ca3Si trigonal pyramid.
Ca2SiO4F crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to one O(2), one O(4), two equivalent O(1), two equivalent O(3), and two equivalent F(1) atoms. The Ca(1)-O(2) bond length is 2.63 Å. The Ca(1)-O(4) bond length is 2.38 Å. There is one shorter (2.38 Å) and one longer (2.45 Å) Ca(1)-O(1) bond length. There is one shorter (2.55 Å) and one longer (2.70 Å) Ca(1)-O(3) bond length. There is one shorter (2.27 Å) and one longer (2.33 Å) Ca(1)-F(1) bond length. In the second Ca site, Ca(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms. The Ca(2)-O(1) bond length is 2.48 Å. The Ca(2)-O(4) bond length is 2.43 Å. There is one shorter (2.35 Å) and one longer (2.49 Å) Ca(2)-O(2) bond length. There is one shorter (2.49 Å) and one longer (2.95 Å) Ca(2)-O(3) bond length. There is one shorter (2.37 Å) and one longer (2.50 Å) Ca(2)-F(1) bond length. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(2) bond length is 1.62 Å. The Si(1)-O(3) bond length is 1.68 Å. The Si(1)-O(4) bond length is 1.66 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(2), two equivalent Ca(1), and one Si(1) atom to form distorted OCa3Si trigonal pyramids that share corners with four equivalent F(1)Ca4 tetrahedra,  an edgeedge with one F(1)Ca4 tetrahedra, and  an edgeedge with one O(1)Ca3Si trigonal pyramid. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal non-coplanar geometry to one Ca(1), one Ca(2), and one Si(1) atom. F(1) is bonded to two equivalent Ca(1) and two equivalent Ca(2) atoms to form distorted FCa4 tetrahedra that share corners with two equivalent F(1)Ca4 tetrahedra, corners with four equivalent O(1)Ca3Si trigonal pyramids,  an edgeedge with one F(1)Ca4 tetrahedra, and  an edgeedge with one O(1)Ca3Si trigonal pyramid.