Eu4O3F7 crystallizes in the monoclinic P2 space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a distorted q6 geometry to one O(1), one O(2), one O(3), one F(1), one F(2), one F(4), one F(5), and two equivalent F(3) atoms. In the second Eu site, Eu(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one F(1), one F(2), one F(3), one F(5), and two equivalent F(4) atoms. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent F(2)Eu4 tetrahedra, corners with four equivalent F(5)Eu4 tetrahedra, edges with two equivalent O(2)Eu4 tetrahedra, edges with two equivalent O(3)Eu4 tetrahedra, and edges with two equivalent F(1)Eu4 tetrahedra. In the second O site, O(2) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent O(3)Eu4 tetrahedra, corners with four equivalent F(1)Eu4 tetrahedra, edges with two equivalent O(1)Eu4 tetrahedra, edges with two equivalent F(2)Eu4 tetrahedra, and edges with two equivalent F(5)Eu4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent O(2)Eu4 tetrahedra, corners with four equivalent F(1)Eu4 tetrahedra, corners with four equivalent F(2)Eu4 tetrahedra, edges with two equivalent O(1)Eu4 tetrahedra, and edges with two equivalent F(5)Eu4 tetrahedra. There are five inequivalent F sites. In the first F site, F(1) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form FEu4 tetrahedra that share corners with four equivalent O(2)Eu4 tetrahedra, corners with four equivalent O(3)Eu4 tetrahedra, corners with four equivalent F(5)Eu4 tetrahedra, edges with two equivalent O(1)Eu4 tetrahedra, and edges with two equivalent F(2)Eu4 tetrahedra. In the second F site, F(2) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form FEu4 tetrahedra that share corners with four equivalent O(1)Eu4 tetrahedra, corners with four equivalent O(3)Eu4 tetrahedra, corners with four equivalent F(5)Eu4 tetrahedra, edges with two equivalent O(2)Eu4 tetrahedra, and edges with two equivalent F(1)Eu4 tetrahedra. In the third F site, F(3) is bonded in a trigonal non-coplanar geometry to one Eu(2) and two equivalent Eu(1) atoms. In the fourth F site, F(4) is bonded in a trigonal non-coplanar geometry to one Eu(1) and two equivalent Eu(2) atoms. In the fifth F site, F(5) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form FEu4 tetrahedra that share corners with four equivalent O(1)Eu4 tetrahedra, corners with four equivalent F(1)Eu4 tetrahedra, corners with four equivalent F(2)Eu4 tetrahedra, edges with two equivalent O(2)Eu4 tetrahedra, and edges with two equivalent O(3)Eu4 tetrahedra.
Eu4O3F7 crystallizes in the monoclinic P2 space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a distorted q6 geometry to one O(1), one O(2), one O(3), one F(1), one F(2), one F(4), one F(5), and two equivalent F(3) atoms. The Eu(1)-O(1) bond length is 2.35 Å. The Eu(1)-O(2) bond length is 2.55 Å. The Eu(1)-O(3) bond length is 2.51 Å. The Eu(1)-F(1) bond length is 2.54 Å. The Eu(1)-F(2) bond length is 2.42 Å. The Eu(1)-F(4) bond length is 2.47 Å. The Eu(1)-F(5) bond length is 2.42 Å. There is one shorter (2.41 Å) and one longer (2.45 Å) Eu(1)-F(3) bond length. In the second Eu site, Eu(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(3), one F(1), one F(2), one F(3), one F(5), and two equivalent F(4) atoms. The Eu(2)-O(1) bond length is 2.50 Å. The Eu(2)-O(2) bond length is 2.37 Å. The Eu(2)-O(3) bond length is 2.39 Å. The Eu(2)-F(1) bond length is 2.44 Å. The Eu(2)-F(2) bond length is 2.64 Å. The Eu(2)-F(3) bond length is 2.41 Å. The Eu(2)-F(5) bond length is 2.56 Å. There is one shorter (2.41 Å) and one longer (2.47 Å) Eu(2)-F(4) bond length. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent F(2)Eu4 tetrahedra, corners with four equivalent F(5)Eu4 tetrahedra, edges with two equivalent O(2)Eu4 tetrahedra, edges with two equivalent O(3)Eu4 tetrahedra, and edges with two equivalent F(1)Eu4 tetrahedra. In the second O site, O(2) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent O(3)Eu4 tetrahedra, corners with four equivalent F(1)Eu4 tetrahedra, edges with two equivalent O(1)Eu4 tetrahedra, edges with two equivalent F(2)Eu4 tetrahedra, and edges with two equivalent F(5)Eu4 tetrahedra. In the third O site, O(3) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form OEu4 tetrahedra that share corners with four equivalent O(2)Eu4 tetrahedra, corners with four equivalent F(1)Eu4 tetrahedra, corners with four equivalent F(2)Eu4 tetrahedra, edges with two equivalent O(1)Eu4 tetrahedra, and edges with two equivalent F(5)Eu4 tetrahedra. There are five inequivalent F sites. In the first F site, F(1) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form FEu4 tetrahedra that share corners with four equivalent O(2)Eu4 tetrahedra, corners with four equivalent O(3)Eu4 tetrahedra, corners with four equivalent F(5)Eu4 tetrahedra, edges with two equivalent O(1)Eu4 tetrahedra, and edges with two equivalent F(2)Eu4 tetrahedra. In the second F site, F(2) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form FEu4 tetrahedra that share corners with four equivalent O(1)Eu4 tetrahedra, corners with four equivalent O(3)Eu4 tetrahedra, corners with four equivalent F(5)Eu4 tetrahedra, edges with two equivalent O(2)Eu4 tetrahedra, and edges with two equivalent F(1)Eu4 tetrahedra. In the third F site, F(3) is bonded in a trigonal non-coplanar geometry to one Eu(2) and two equivalent Eu(1) atoms. In the fourth F site, F(4) is bonded in a trigonal non-coplanar geometry to one Eu(1) and two equivalent Eu(2) atoms. In the fifth F site, F(5) is bonded to two equivalent Eu(1) and two equivalent Eu(2) atoms to form FEu4 tetrahedra that share corners with four equivalent O(1)Eu4 tetrahedra, corners with four equivalent F(1)Eu4 tetrahedra, corners with four equivalent F(2)Eu4 tetrahedra, edges with two equivalent O(2)Eu4 tetrahedra, and edges with two equivalent O(3)Eu4 tetrahedra.