CaH4(C5O2)2(CH)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure consists of eight 02329_fluka molecules inside a CaH4(C5O2)2 framework. In the CaH4(C5O2)2 framework, Ca(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted edge-sharing CaO6 octahedra. The Ca(1)-O(3) bond length is 2.33 Å. The Ca(1)-O(4) bond length is 2.31 Å. There is one shorter (2.45 Å) and one longer (2.53 Å) Ca(1)-O(1) bond length. There is one shorter (2.44 Å) and one longer (2.49 Å) Ca(1)-O(2) bond length. There are ten inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one C(3), one O(1), and one O(2) atom. The C(1)-C(3) bond length is 1.50 Å. The C(1)-O(1) bond length is 1.26 Å. The C(1)-O(2) bond length is 1.26 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(3), and one O(4) atom. The C(2)-C(6) bond length is 1.51 Å. The C(2)-O(3) bond length is 1.25 Å. The C(2)-O(4) bond length is 1.25 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(1), one C(4), and one C(8) atom. The C(3)-C(4) bond length is 1.35 Å. The C(3)-C(8) bond length is 1.42 Å. In the fourth C site, C(4) is bonded in a single-bond geometry to one C(3) and one H(1) atom. The C(4)-H(1) bond length is 0.93 Å. In the fifth C site, C(5) is bonded in a single-bond geometry to one C(6) and one H(2) atom. The C(5)-C(6) bond length is 1.36 Å. The C(5)-H(2) bond length is 0.93 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one C(2), one C(5), and one C(7) atom. The C(6)-C(7) bond length is 1.41 Å. In the seventh C site, C(7) is bonded in a trigonal planar geometry to one C(12), one C(6), and one C(8) atom. The C(7)-C(12) bond length is 1.43 Å. The C(7)-C(8) bond length is 1.43 Å. In the eighth C site, C(8) is bonded in a trigonal planar geometry to one C(3), one C(7), and one C(9) atom. The C(8)-C(9) bond length is 1.39 Å. In the ninth C site, C(9) is bonded in a distorted single-bond geometry to one C(8) and one H(3) atom. The C(9)-H(3) bond length is 0.93 Å. In the tenth C site, C(12) is bonded in a distorted single-bond geometry to one C(7) and one H(6) atom. The C(12)-H(6) bond length is 0.93 Å. There are four inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(4) atom. In the second H site, H(2) is bonded in a single-bond geometry to one C(5) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(9) atom. In the fourth H site, H(6) is bonded in a single-bond geometry to one C(12) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ca(1) and one C(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Ca(1) and one C(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ca(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one C(2) atom. Linkers: 4 [O]C(=O)c1ccc(C([O])=O)c2ccccc12. Metal clusters: 4 [Ca]. The MOF has largest included sphere 3.82 A, density 1.18 g/cm3, surface area 4423.98 m2/g, accessible volume 0.36 cm3/g