Mn3Si(O2F)2 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent F(1) atoms to form distorted MnO4F2 octahedra that share corners with eight equivalent Mn(2)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mn(2)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-59°. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent F(1) atoms to form MnO4F2 octahedra that share corners with two equivalent Mn(2)O4F2 octahedra, corners with four equivalent Mn(1)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Mn(1)O4F2 octahedra, edges with two equivalent Mn(2)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-63°. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Mn(1)O4F2 octahedra, corners with four equivalent Mn(2)O4F2 octahedra,  an edgeedge with one Mn(1)O4F2 octahedra, and edges with two equivalent Mn(2)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 53-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mn(1), two equivalent Mn(2), and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Si(1) atom. F(1) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(2) atoms.
Mn3Si(O2F)2 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent F(1) atoms to form distorted MnO4F2 octahedra that share corners with eight equivalent Mn(2)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mn(2)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-59°. The Mn(1)-O(1) bond length is 2.42 Å. The Mn(1)-O(2) bond length is 2.14 Å. Both Mn(1)-O(3) bond lengths are 2.30 Å. Both Mn(1)-F(1) bond lengths are 2.15 Å. In the second Mn site, Mn(2) is bonded to one O(1), one O(2), two equivalent O(3), and two equivalent F(1) atoms to form MnO4F2 octahedra that share corners with two equivalent Mn(2)O4F2 octahedra, corners with four equivalent Mn(1)O4F2 octahedra, corners with two equivalent Si(1)O4 tetrahedra,  an edgeedge with one Mn(1)O4F2 octahedra, edges with two equivalent Mn(2)O4F2 octahedra, and  an edgeedge with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 48-63°. The Mn(2)-O(1) bond length is 2.24 Å. The Mn(2)-O(2) bond length is 2.31 Å. There is one shorter (2.12 Å) and one longer (2.25 Å) Mn(2)-O(3) bond length. There is one shorter (2.15 Å) and one longer (2.20 Å) Mn(2)-F(1) bond length. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Mn(1)O4F2 octahedra, corners with four equivalent Mn(2)O4F2 octahedra,  an edgeedge with one Mn(1)O4F2 octahedra, and edges with two equivalent Mn(2)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 53-60°. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.66 Å. Both Si(1)-O(3) bond lengths are 1.66 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mn(1), two equivalent Mn(2), and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Mn(1), two equivalent Mn(2), and one Si(1) atom. F(1) is bonded in a trigonal planar geometry to one Mn(1) and two equivalent Mn(2) atoms.