Sr5CaAl2(O4F)2 crystallizes in the orthorhombic Fmm2 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), four equivalent O(3), and two equivalent F(1) atoms. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent O(1), four equivalent O(3), and two equivalent F(1) atoms. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), four equivalent O(3), and two equivalent F(1) atoms. Al(1) is bonded in a tetrahedral geometry to one O(1), one O(2), and two equivalent O(3) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Sr(2), two equivalent Sr(1), two equivalent Sr(3), and one Al(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), one Ca(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), two equivalent Sr(1), one Ca(1), and one Al(1) atom. F(1) is bonded to one Sr(2), two equivalent Sr(1), two equivalent Sr(3), and one Ca(1) atom to form corner-sharing FSr5Ca octahedra. The corner-sharing octahedral tilt angles range from 0-37°.
Sr5CaAl2(O4F)2 crystallizes in the orthorhombic Fmm2 space group. There are three inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a distorted q6 geometry to two equivalent O(1), two equivalent O(2), four equivalent O(3), and two equivalent F(1) atoms. Both Sr(1)-O(1) bond lengths are 2.85 Å. Both Sr(1)-O(2) bond lengths are 2.86 Å. There are two shorter (2.81 Å) and two longer (2.88 Å) Sr(1)-O(3) bond lengths. Both Sr(1)-F(1) bond lengths are 2.80 Å. In the second Sr site, Sr(2) is bonded in a 8-coordinate geometry to two equivalent O(1), four equivalent O(3), and two equivalent F(1) atoms. Both Sr(2)-O(1) bond lengths are 2.46 Å. All Sr(2)-O(3) bond lengths are 2.66 Å. Both Sr(2)-F(1) bond lengths are 2.60 Å. In the third Sr site, Sr(3) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent F(1) atoms. Both Sr(3)-O(1) bond lengths are 2.68 Å. Both Sr(3)-O(2) bond lengths are 2.69 Å. Both Sr(3)-O(3) bond lengths are 2.46 Å. Both Sr(3)-F(1) bond lengths are 2.51 Å. Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(2), four equivalent O(3), and two equivalent F(1) atoms. Both Ca(1)-O(2) bond lengths are 2.36 Å. All Ca(1)-O(3) bond lengths are 2.70 Å. Both Ca(1)-F(1) bond lengths are 2.46 Å. Al(1) is bonded in a tetrahedral geometry to one O(1), one O(2), and two equivalent O(3) atoms. The Al(1)-O(1) bond length is 1.79 Å. The Al(1)-O(2) bond length is 1.81 Å. Both Al(1)-O(3) bond lengths are 1.79 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Sr(2), two equivalent Sr(1), two equivalent Sr(3), and one Al(1) atom. In the second O site, O(2) is bonded in a 6-coordinate geometry to two equivalent Sr(1), two equivalent Sr(3), one Ca(1), and one Al(1) atom. In the third O site, O(3) is bonded in a 6-coordinate geometry to one Sr(2), one Sr(3), two equivalent Sr(1), one Ca(1), and one Al(1) atom. F(1) is bonded to one Sr(2), two equivalent Sr(1), two equivalent Sr(3), and one Ca(1) atom to form corner-sharing FSr5Ca octahedra. The corner-sharing octahedral tilt angles range from 0-37°.