Er3C11P2H4O30 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Er sites. In the first Er site, Er(1) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(13), one O(14), one O(18), one O(4), one O(7), and one O(8) atom. The Er(1)-O(11) bond length is 2.40 Å. The Er(1)-O(12) bond length is 2.33 Å. The Er(1)-O(13) bond length is 2.47 Å. The Er(1)-O(14) bond length is 2.39 Å. The Er(1)-O(18) bond length is 2.27 Å. The Er(1)-O(4) bond length is 2.29 Å. The Er(1)-O(7) bond length is 2.33 Å. The Er(1)-O(8) bond length is 2.39 Å. In the second Er site, Er(2) is bonded in a 8-coordinate geometry to one O(15), one O(16), one O(17), one O(23), one O(24), one O(26), one O(5), and one O(6) atom. The Er(2)-O(15) bond length is 2.43 Å. The Er(2)-O(16) bond length is 2.36 Å. The Er(2)-O(17) bond length is 2.25 Å. The Er(2)-O(23) bond length is 2.32 Å. The Er(2)-O(24) bond length is 2.42 Å. The Er(2)-O(26) bond length is 2.29 Å. The Er(2)-O(5) bond length is 2.37 Å. The Er(2)-O(6) bond length is 2.38 Å. In the third Er site, Er(3) is bonded in a 8-coordinate geometry to one O(10), one O(21), one O(22), one O(27), one O(29), one O(3), one O(30), and one O(9) atom. The Er(3)-O(10) bond length is 2.35 Å. The Er(3)-O(21) bond length is 2.34 Å. The Er(3)-O(22) bond length is 2.35 Å. The Er(3)-O(27) bond length is 2.31 Å. The Er(3)-O(29) bond length is 2.44 Å. The Er(3)-O(3) bond length is 2.23 Å. The Er(3)-O(30) bond length is 2.43 Å. The Er(3)-O(9) bond length is 2.38 Å. There are eleven inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(7) atom. The C(1)-O(5) bond length is 1.25 Å. The C(1)-O(7) bond length is 1.26 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(6) and one O(8) atom. The C(2)-O(6) bond length is 1.27 Å. The C(2)-O(8) bond length is 1.25 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(11) and one O(9) atom. The C(3)-O(11) bond length is 1.24 Å. The C(3)-O(9) bond length is 1.28 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(10) and one O(12) atom. The C(4)-O(10) bond length is 1.25 Å. The C(4)-O(12) bond length is 1.24 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one O(14) and one O(16) atom. The C(5)-O(14) bond length is 1.25 Å. The C(5)-O(16) bond length is 1.26 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one O(13) and one O(15) atom. The C(6)-O(13) bond length is 1.26 Å. The C(6)-O(15) bond length is 1.26 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one O(21) and one O(23) atom. The C(7)-O(21) bond length is 1.25 Å. The C(7)-O(23) bond length is 1.26 Å. In the eighth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one O(22) and one O(24) atom. The C(8)-O(22) bond length is 1.26 Å. The C(8)-O(24) bond length is 1.26 Å. In the ninth C site, C(9) is bonded in a distorted bent 120 degrees geometry to one O(26) and one O(28) atom. The C(9)-O(26) bond length is 1.26 Å. The C(9)-O(28) bond length is 1.23 Å. In the tenth C site, C(10) is bonded in a distorted bent 120 degrees geometry to one O(25) and one O(27) atom. The C(10)-O(25) bond length is 1.24 Å. The C(10)-O(27) bond length is 1.26 Å. In the eleventh C site, C(11) is bonded in a distorted bent 120 degrees geometry to one O(29) and one O(30) atom. The C(11)-O(29) bond length is 1.23 Å. The C(11)-O(30) bond length is 1.27 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The P(1)-O(1) bond length is 1.56 Å. The P(1)-O(2) bond length is 1.59 Å. The P(1)-O(3) bond length is 1.50 Å. The P(1)-O(4) bond length is 1.50 Å. In the second P site, P(2) is bonded in a tetrahedral geometry to one O(17), one O(18), one O(19), and one O(20) atom. The P(2)-O(17) bond length is 1.49 Å. The P(2)-O(18) bond length is 1.48 Å. The P(2)-O(19) bond length is 1.57 Å. The P(2)-O(20) bond length is 1.59 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a distorted single-bond geometry to one O(1) and one O(28) atom. The H(1)-O(1) bond length is 0.98 Å. The H(1)-O(28) bond length is 1.65 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. The H(2)-O(2) bond length is 0.94 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(19) and one O(25) atom. The H(3)-O(19) bond length is 0.93 Å. The H(3)-O(25) bond length is 1.71 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(20) atom. The H(4)-O(20) bond length is 0.98 Å. There are thirty inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one P(1) and one H(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one P(1) and one H(2) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Er(3) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Er(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Er(2) and one C(1) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Er(2) and one C(2) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Er(1) and one C(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Er(1) and one C(2) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Er(3) and one C(3) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Er(3) and one C(4) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Er(1) and one C(3) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one Er(1) and one C(4) atom. In the thirteenth O site, O(13) is bonded in a distorted bent 120 degrees geometry to one Er(1) and one C(6) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Er(1) and one C(5) atom. In the fifteenth O site, O(15) is bonded in a bent 120 degrees geometry to one Er(2) and one C(6) atom. In the sixteenth O site, O(16) is bonded in a bent 120 degrees geometry to one Er(2) and one C(5) atom. In the seventeenth O site, O(17) is bonded in a bent 150 degrees geometry to one Er(2) and one P(2) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Er(1) and one P(2) atom. In the nineteenth O site, O(19) is bonded in a water-like geometry to one P(2) and one H(3) atom. In the twentieth O site, O(20) is bonded in a water-like geometry to one P(2) and one H(4) atom. In the twenty-first O site, O(21) is bonded in a distorted bent 120 degrees geometry to one Er(3) and one C(7) atom. In the twenty-second O site, O(22) is bonded in a bent 120 degrees geometry to one Er(3) and one C(8) atom. In the twenty-third O site, O(23) is bonded in a bent 120 degrees geometry to one Er(2) and one C(7) atom. In the twenty-fourth O site, O(24) is bonded in a distorted bent 120 degrees geometry to one Er(2) and one C(8) atom. In the twenty-fifth O site, O(25) is bonded in a distorted single-bond geometry to one C(10) and one H(3) atom. In the twenty-sixth O site, O(26) is bonded in a distorted bent 120 degrees geometry to one Er(2) and one C(9) atom. In the twenty-seventh O site, O(27) is bonded in a distorted bent 120 degrees geometry to one Er(3) and one C(10) atom. In the twenty-eighth O site, O(28) is bonded in a distorted bent 120 degrees geometry to one C(9) and one H(1) atom. In the twenty-ninth O site, O(29) is bonded in a distorted bent 120 degrees geometry to one Er(3) and one C(11) atom. In the thirtieth O site, O(30) is bonded in a bent 120 degrees geometry to one Er(3) and one C(11) atom. Linkers: 22 [O]C(=O)C([O])=O. Metal clusters: 12 [Er]. The MOF has largest included sphere 4.93 A, density 2.00 g/cm3, surface area 2288.84 m2/g, accessible volume 0.27 cm3/g