Er2C15H11O16 crystallizes in the triclinic P-1 space group. There are two inequivalent Er sites. In the first Er site, Er(1) is bonded in a 9-coordinate geometry to one O(10), one O(11), one O(12), one O(13), one O(14), one O(7), one O(9), and two equivalent O(15) atoms. The Er(1)-O(10) bond length is 2.37 Å. The Er(1)-O(11) bond length is 2.48 Å. The Er(1)-O(12) bond length is 2.33 Å. The Er(1)-O(13) bond length is 2.28 Å. The Er(1)-O(14) bond length is 2.63 Å. The Er(1)-O(7) bond length is 2.39 Å. The Er(1)-O(9) bond length is 2.36 Å. There is one shorter (2.36 Å) and one longer (2.44 Å) Er(1)-O(15) bond length. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), one O(7), and one O(8) atom. The Er(2)-O(1) bond length is 2.48 Å. The Er(2)-O(2) bond length is 2.34 Å. The Er(2)-O(3) bond length is 2.39 Å. The Er(2)-O(4) bond length is 2.38 Å. The Er(2)-O(5) bond length is 2.19 Å. The Er(2)-O(6) bond length is 2.37 Å. The Er(2)-O(7) bond length is 2.46 Å. The Er(2)-O(8) bond length is 2.19 Å. There are fifteen inequivalent C sites. In the first C site, C(1) is bonded in a bent 120 degrees geometry to one C(2), one O(14), and one O(15) atom. The C(1)-C(2) bond length is 1.49 Å. The C(1)-O(14) bond length is 1.26 Å. The C(1)-O(15) bond length is 1.29 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(1), one C(3), and one C(4) atom. The C(2)-C(3) bond length is 1.40 Å. The C(2)-C(4) bond length is 1.41 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(2), one C(4), and one H(1) atom. The C(3)-C(4) bond length is 1.40 Å. The C(3)-H(1) bond length is 1.09 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one C(2), one C(3), and one C(8) atom. The C(4)-C(8) bond length is 1.50 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(12), and one O(13) atom. The C(5)-C(6) bond length is 1.50 Å. The C(5)-O(12) bond length is 1.27 Å. The C(5)-O(13) bond length is 1.27 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(15), one C(5), and one C(7) atom. The C(6)-C(15) bond length is 1.41 Å. The C(6)-C(7) bond length is 1.40 Å. In the seventh C site, C(7) is bonded in a distorted single-bond geometry to one C(15), one C(6), and one H(2) atom. The C(7)-C(15) bond length is 1.39 Å. The C(7)-H(2) bond length is 1.09 Å. In the eighth C site, C(8) is bonded in a bent 120 degrees geometry to one C(4), one O(6), and one O(7) atom. The C(8)-O(6) bond length is 1.27 Å. The C(8)-O(7) bond length is 1.29 Å. In the ninth C site, C(9) is bonded in a distorted bent 120 degrees geometry to one C(12), one O(16), and one O(5) atom. The C(9)-C(12) bond length is 1.50 Å. The C(9)-O(16) bond length is 1.27 Å. The C(9)-O(5) bond length is 1.28 Å. In the tenth C site, C(10) is bonded in a trigonal planar geometry to one C(11), one C(12), and one C(13) atom. The C(10)-C(11) bond length is 1.40 Å. The C(10)-C(12) bond length is 1.41 Å. The C(10)-C(13) bond length is 1.50 Å. In the eleventh C site, C(11) is bonded in a distorted single-bond geometry to one C(10), one C(12), and one H(3) atom. The C(11)-C(12) bond length is 1.40 Å. The C(11)-H(3) bond length is 1.09 Å. In the twelfth C site, C(12) is bonded in a trigonal planar geometry to one C(10), one C(11), and one C(9) atom. In the thirteenth C site, C(13) is bonded in a distorted bent 120 degrees geometry to one C(10), one O(8), and one O(9) atom. The C(13)-O(8) bond length is 1.27 Å. The C(13)-O(9) bond length is 1.28 Å. In the fourteenth C site, C(14) is bonded in a bent 120 degrees geometry to one C(15), one O(1), and one O(2) atom. The C(14)-C(15) bond length is 1.49 Å. The C(14)-O(1) bond length is 1.27 Å. The C(14)-O(2) bond length is 1.30 Å. In the fifteenth C site, C(15) is bonded in a trigonal planar geometry to one C(14), one C(6), and one C(7) atom. There are eleven inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(7) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(11) atom. In the fourth H site, H(4) is bonded in a linear geometry to one O(2) and one O(3) atom. The H(4)-O(2) bond length is 1.56 Å. The H(4)-O(3) bond length is 1.02 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(3) atom. The H(5)-O(3) bond length is 0.98 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(4) atom. The H(6)-O(4) bond length is 0.99 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(4) atom. The H(7)-O(4) bond length is 0.99 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(10) atom. The H(8)-O(10) bond length is 0.97 Å. In the ninth H site, H(9) is bonded in a single-bond geometry to one O(10) atom. The H(9)-O(10) bond length is 1.00 Å. In the tenth H site, H(10) is bonded in a single-bond geometry to one O(11) atom. The H(10)-O(11) bond length is 0.98 Å. In the eleventh H site, H(11) is bonded in a single-bond geometry to one O(11) atom. The H(11)-O(11) bond length is 0.99 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Er(2) and one C(14) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Er(2), one C(14), and one H(4) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to one Er(2), one H(4), and one H(5) atom. In the fourth O site, O(4) is bonded in a distorted water-like geometry to one Er(2), one H(6), and one H(7) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Er(2) and one C(9) atom. In the sixth O site, O(6) is bonded in a distorted single-bond geometry to one Er(2) and one C(8) atom. In the seventh O site, O(7) is bonded in a distorted single-bond geometry to one Er(1), one Er(2), and one C(8) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Er(2) and one C(13) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Er(1) and one C(13) atom. In the tenth O site, O(10) is bonded in a distorted water-like geometry to one Er(1), one H(8), and one H(9) atom. In the eleventh O site, O(11) is bonded in a water-like geometry to one Er(1), one H(10), and one H(11) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one Er(1) and one C(5) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one C(5) atom. In the fourteenth O site, O(14) is bonded in a single-bond geometry to one Er(1) and one C(1) atom. In the fifteenth O site, O(15) is bonded in a distorted single-bond geometry to two equivalent Er(1) and one C(1) atom. In the sixteenth O site, O(16) is bonded in a distorted single-bond geometry to one C(9) atom. Linkers: 3 [O]C(=O)c1cc(C([O])=O)c(C([O])=O)cc1C([O])=O. Metal clusters: 1 O.O.O.O.O.O.O.O.O=[C]O[Er]1(O[C]=O)O[C]O[Er]2(O[C]=O)(O[C]O1)O[C]O[Er]1(O[C]=O)(O[C]O[Er](O[C]=O)(O[C]=O)O[C]O1)O[C]O2. The MOF has largest included sphere 3.22 A, density 2.54 g/cm3, surface area 2139.55 m2/g, accessible volume 0.11 cm3/g