Eu5Si3O12F crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), four equivalent O(2), and one F(1) atom. In the second Eu site, Eu(2) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(3), and two equivalent O(2) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Eu(1), two equivalent Eu(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one Eu(2), two equivalent Eu(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Eu(1), two equivalent Eu(2), and one Si(1) atom. F(1) is bonded in a trigonal planar geometry to three equivalent Eu(1) atoms.
Eu5Si3O12F crystallizes in the hexagonal P6_3/m space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), four equivalent O(2), and one F(1) atom. The Eu(1)-O(1) bond length is 2.38 Å. The Eu(1)-O(3) bond length is 2.77 Å. There are two shorter (2.39 Å) and two longer (2.53 Å) Eu(1)-O(2) bond lengths. The Eu(1)-F(1) bond length is 2.44 Å. In the second Eu site, Eu(2) is bonded in a 9-coordinate geometry to three equivalent O(1), three equivalent O(2), and three equivalent O(3) atoms. All Eu(2)-O(1) bond lengths are 2.51 Å. All Eu(2)-O(2) bond lengths are 2.89 Å. All Eu(2)-O(3) bond lengths are 2.45 Å. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(3), and two equivalent O(2) atoms. The Si(1)-O(1) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.63 Å. Both Si(1)-O(2) bond lengths are 1.65 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Eu(1), two equivalent Eu(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to one Eu(2), two equivalent Eu(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Eu(1), two equivalent Eu(2), and one Si(1) atom. F(1) is bonded in a trigonal planar geometry to three equivalent Eu(1) atoms.