Eu3S7O29 crystallizes in the trigonal P31c space group. Eu(1) is bonded in a 9-coordinate geometry to one O(1), one O(11), one O(2), one O(3), one O(4), one O(6), one O(7), and two equivalent O(9) atoms. The Eu(1)-O(1) bond length is 2.50 Å. The Eu(1)-O(11) bond length is 2.51 Å. The Eu(1)-O(2) bond length is 2.46 Å. The Eu(1)-O(3) bond length is 2.46 Å. The Eu(1)-O(4) bond length is 2.56 Å. The Eu(1)-O(6) bond length is 2.34 Å. The Eu(1)-O(7) bond length is 2.38 Å. There is one shorter (2.49 Å) and one longer (2.66 Å) Eu(1)-O(9) bond length. There are three inequivalent S sites. In the first S site, S(1) is bonded in a tetrahedral geometry to one O(5), one O(6), one O(7), and one O(8) atom. The S(1)-O(5) bond length is 1.48 Å. The S(1)-O(6) bond length is 1.47 Å. The S(1)-O(7) bond length is 1.48 Å. The S(1)-O(8) bond length is 1.46 Å. In the second S site, S(2) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The S(2)-O(1) bond length is 1.47 Å. The S(2)-O(2) bond length is 1.48 Å. The S(2)-O(3) bond length is 1.47 Å. The S(2)-O(4) bond length is 1.48 Å. In the third S site, S(3) is bonded in a tetrahedral geometry to one O(10) and three equivalent O(9) atoms. The S(3)-O(10) bond length is 1.43 Å. All S(3)-O(9) bond lengths are 1.50 Å. There are eleven inequivalent O sites. In the first O site, O(10) is bonded in a single-bond geometry to one S(3) atom. In the second O site, O(11) is bonded in a trigonal non-coplanar geometry to three equivalent Eu(1) atoms. In the third O site, O(1) is bonded in a distorted single-bond geometry to one Eu(1) and one S(2) atom. In the fourth O site, O(2) is bonded in a distorted water-like geometry to one Eu(1) and one S(2) atom. In the fifth O site, O(3) is bonded in a distorted water-like geometry to one Eu(1) and one S(2) atom. In the sixth O site, O(4) is bonded in a distorted single-bond geometry to one Eu(1) and one S(2) atom. In the seventh O site, O(5) is bonded in a single-bond geometry to one S(1) atom. In the eighth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Eu(1) and one S(1) atom. In the ninth O site, O(7) is bonded in a distorted bent 120 degrees geometry to one Eu(1) and one S(1) atom. In the tenth O site, O(8) is bonded in a single-bond geometry to one S(1) atom. In the eleventh O site, O(9) is bonded in a distorted single-bond geometry to two equivalent Eu(1) and one S(3) atom. Linkers: 14 [O]S([O])(=O)=O. Metal clusters: 6 [Eu]. The MOF has largest included sphere 4.42 A, density 2.12 g/cm3, surface area 2281.97 m2/g, accessible volume 0.21 cm3/g