CdH4(C3N4)2 crystallizes in the trigonal P3_121 space group. Cd(1) is bonded to one N(1), one N(2), one N(3), one N(4), one N(5), and one N(6) atom to form corner-sharing CdN6 octahedra. The corner-sharing octahedral tilt angles are 68°. The Cd(1)-N(1) bond length is 2.33 Å. The Cd(1)-N(2) bond length is 2.38 Å. The Cd(1)-N(3) bond length is 2.34 Å. The Cd(1)-N(4) bond length is 2.40 Å. The Cd(1)-N(5) bond length is 2.49 Å. The Cd(1)-N(6) bond length is 2.43 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(2), one C(3), and one C(6) atom. The C(1)-C(2) bond length is 1.40 Å. The C(1)-C(3) bond length is 1.40 Å. The C(1)-C(6) bond length is 1.46 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one C(1), one N(2), and one H(1) atom. The C(2)-N(2) bond length is 1.34 Å. The C(2)-H(1) bond length is 1.09 Å. In the third C site, C(3) is bonded in a distorted single-bond geometry to one C(1) and one H(2) atom. The C(3)-H(2) bond length is 1.08 Å. In the fourth C site, C(4) is bonded in a distorted trigonal planar geometry to one C(5), one N(2), and one H(3) atom. The C(4)-C(5) bond length is 1.39 Å. The C(4)-N(2) bond length is 1.35 Å. The C(4)-H(3) bond length is 1.09 Å. In the fifth C site, C(5) is bonded in a distorted single-bond geometry to one C(4) and one H(4) atom. The C(5)-H(4) bond length is 1.09 Å. In the sixth C site, C(6) is bonded in a distorted trigonal planar geometry to one C(1), one N(4), and one N(5) atom. The C(6)-N(4) bond length is 1.35 Å. The C(6)-N(5) bond length is 1.35 Å. There are ten inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to two equivalent Cd(1) and one N(8) atom. The N(1)-N(8) bond length is 1.21 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one Cd(1), one C(2), and one C(4) atom. In the third N site, N(3) is bonded in a distorted bent 150 degrees geometry to one Cd(1) and one N(9) atom. The N(3)-N(9) bond length is 1.18 Å. In the fourth N site, N(4) is bonded in a 3-coordinate geometry to one Cd(1), one C(6), and one N(7) atom. The N(4)-N(7) bond length is 1.34 Å. In the fifth N site, N(5) is bonded in a 3-coordinate geometry to one Cd(1), one C(6), and one N(6) atom. The N(5)-N(6) bond length is 1.35 Å. In the sixth N site, N(6) is bonded in a trigonal planar geometry to one Cd(1), one N(5), and one N(7) atom. The N(6)-N(7) bond length is 1.31 Å. In the seventh N site, N(7) is bonded in a water-like geometry to one N(4) and one N(6) atom. In the eighth N site, N(8) is bonded in a linear geometry to one N(1) and one N(10) atom. The N(8)-N(10) bond length is 1.16 Å. In the ninth N site, N(9) is bonded in a linear geometry to two equivalent N(3) atoms. In the tenth N site, N(10) is bonded in a single-bond geometry to one N(8) atom. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(2) 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) is bonded in a single-bond geometry to one C(4) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(5) atom. Linkers: 6 c1cncc(C2=NN=N[N]2)c1. Metal clusters: 6 [Cd]. The MOF has largest included sphere 3.92 A, density 2.02 g/cm3, surface area 3210.89 m2/g, accessible volume 0.14 cm3/g