Eu2MoC20H10(N3O)4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Eu sites. In the first Eu site, Eu(1) is bonded in a 7-coordinate geometry to one N(1), one N(3), one N(5), one N(6), one N(7), one O(2), and one O(4) atom. The Eu(1)-N(1) bond length is 2.62 Å. The Eu(1)-N(3) bond length is 2.63 Å. The Eu(1)-N(5) bond length is 2.49 Å. The Eu(1)-N(6) bond length is 2.47 Å. The Eu(1)-N(7) bond length is 2.45 Å. The Eu(1)-O(2) bond length is 2.42 Å. The Eu(1)-O(4) bond length is 2.40 Å. In the second Eu site, Eu(2) is bonded in an L-shaped geometry to one O(1) and one O(3) atom. The Eu(2)-O(1) bond length is 2.43 Å. The Eu(2)-O(3) bond length is 2.33 Å. Mo(1) is bonded in a 8-coordinate geometry to one C(13), one C(14), one C(15), one C(16), one C(17), one C(18), one C(19), and one C(20) atom. The Mo(1)-C(13) bond length is 2.14 Å. The Mo(1)-C(14) bond length is 2.14 Å. The Mo(1)-C(15) bond length is 2.13 Å. The Mo(1)-C(16) bond length is 2.15 Å. The Mo(1)-C(17) bond length is 2.14 Å. The Mo(1)-C(18) bond length is 2.17 Å. The Mo(1)-C(19) bond length is 2.15 Å. The Mo(1)-C(20) bond length is 2.17 Å. There are twenty inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to one C(2), one N(1), and one H(1) atom. The C(1)-C(2) bond length is 1.38 Å. The C(1)-N(1) bond length is 1.33 Å. The C(1)-H(1) bond length is 0.94 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one C(5), and one N(2) atom. The C(2)-C(5) bond length is 1.49 Å. The C(2)-N(2) bond length is 1.33 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(4), one N(2), and one H(2) atom. The C(3)-C(4) bond length is 1.38 Å. The C(3)-N(2) bond length is 1.33 Å. The C(3)-H(2) bond length is 0.94 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(3), one C(6), and one N(1) atom. The C(4)-C(6) bond length is 1.50 Å. The C(4)-N(1) bond length is 1.34 Å. In the fifth C site, C(5) is bonded in a trigonal non-coplanar geometry to one C(2) and three equivalent H(3,4,5) atoms. All C(5)-H(3,4,5) bond lengths are 0.97 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(1), and one O(2) atom. The C(6)-O(1) bond length is 1.24 Å. The C(6)-O(2) bond length is 1.25 Å. In the seventh C site, C(7) is bonded in a distorted trigonal planar geometry to one C(8), one N(3), and one H(6) atom. The C(7)-C(8) bond length is 1.38 Å. The C(7)-N(3) bond length is 1.32 Å. The C(7)-H(6) bond length is 0.94 Å. In the eighth C site, C(8) is bonded in a distorted trigonal planar geometry to one C(11), one C(7), and one N(4) atom. The C(8)-C(11) bond length is 1.49 Å. The C(8)-N(4) bond length is 1.33 Å. In the ninth C site, C(9) is bonded in a distorted trigonal planar geometry to one C(10), one N(4), and one H(7) atom. The C(9)-C(10) bond length is 1.38 Å. The C(9)-N(4) bond length is 1.33 Å. The C(9)-H(7) bond length is 0.94 Å. In the tenth C site, C(10) is bonded in a distorted trigonal planar geometry to one C(12), one C(9), and one N(3) atom. The C(10)-C(12) bond length is 1.48 Å. The C(10)-N(3) bond length is 1.34 Å. In the eleventh C site, C(11) is bonded in a trigonal non-coplanar geometry to one C(8), one H(10), one H(8), and one H(9) atom. The C(11)-H(10) bond length is 0.97 Å. The C(11)-H(8) bond length is 0.97 Å. The C(11)-H(9) bond length is 0.97 Å. In the twelfth C site, C(12) is bonded in a distorted bent 120 degrees geometry to one C(10), one O(3), and one O(4) atom. The C(12)-O(3) bond length is 1.25 Å. The C(12)-O(4) bond length is 1.25 Å. In the thirteenth C site, C(13) is bonded in a distorted linear geometry to one Mo(1) and one N(5) atom. The C(13)-N(5) bond length is 1.14 Å. In the fourteenth C site, C(14) is bonded in a distorted linear geometry to one Mo(1) and one N(6) atom. The C(14)-N(6) bond length is 1.15 Å. In the fifteenth C site, C(15) is bonded in a linear geometry to one Mo(1) and one N(7) atom. The C(15)-N(7) bond length is 1.14 Å. In the sixteenth C site, C(16) is bonded in a linear geometry to one Mo(1) and one N(8) atom. The C(16)-N(8) bond length is 1.14 Å. In the seventeenth C site, C(17) is bonded in a linear geometry to one Mo(1) and one N(9,12) atom. The C(17)-N(9,12) bond length is 1.14 Å. In the eighteenth C site, C(18) is bonded in a linear geometry to one Mo(1) and one N(10) atom. The C(18)-N(10) bond length is 1.14 Å. In the nineteenth C site, C(19) is bonded in a linear geometry to one Mo(1) and one N(11) atom. The C(19)-N(11) bond length is 1.14 Å. In the twentieth C site, C(20) is bonded in a distorted linear geometry to one Mo(1) and one N(9,12) atom. The C(20)-N(9,12) bond length is 1.14 Å. There are eleven inequivalent N sites. In the first N site, N(1) is bonded in a distorted trigonal planar geometry to one Eu(1), one C(1), and one C(4) atom. In the second N site, N(2) is bonded in a bent 120 degrees geometry to one C(2) and one C(3) atom. In the third N site, N(3) is bonded in a distorted bent 120 degrees geometry to one Eu(1), one C(10), and one C(7) atom. In the fourth N site, N(4) is bonded in a bent 120 degrees geometry to one C(8) and one C(9) atom. In the fifth N site, N(5) is bonded in a distorted bent 150 degrees geometry to one Eu(1) and one C(13) atom. In the sixth N site, N(6) is bonded in a distorted linear geometry to one Eu(1) and one C(14) atom. In the seventh N site, N(7) is bonded in a linear geometry to one Eu(1) and one C(15) atom. In the eighth N site, N(8) is bonded in a single-bond geometry to one C(16) atom. In the ninth N site, N(9,12) is bonded in a single-bond geometry to one C(17) atom. In the tenth N site, N(10) is bonded in a single-bond geometry to one C(18) atom. In the eleventh N site, N(11) is bonded in a single-bond geometry to one C(19) atom. There are eight inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(3) atom. In the third H site, H(3,4,5) is bonded in a single-bond geometry to one C(5) atom. In the fourth H site, H(6) is bonded in a single-bond geometry to one C(7) atom. In the fifth H site, H(7) is bonded in a single-bond geometry to one C(9) atom. In the sixth H site, H(8) is bonded in a single-bond geometry to one C(11) atom. In the seventh H site, H(9) is bonded in a single-bond geometry to one C(11) atom. In the eighth H site, H(10) is bonded in a single-bond geometry to one C(11) atom. There are four inequivalent O sites. In the first O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Eu(1) and one C(6) atom. In the second O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Eu(2) and one C(12) atom. In the third O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Eu(1) and one C(12) atom. In the fourth O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Eu(2) and one C(6) atom. Linkers: 8 Cc1cnc(C([O])=O)cn1 ,12 [C]#N. Metal clusters: 8 [Eu] ,4 [Mo]. The MOF has largest included sphere 5.89 A, density 1.49 g/cm3, surface area 3344.79 m2/g, accessible volume 0.29 cm3/g