CaC5H8O8Br crystallizes in the triclinic P-1 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(5), one O(6), one O(7), one O(8), two equivalent O(2), and two equivalent O(3) atoms. The Ca(1)-O(5) bond length is 2.45 Å. The Ca(1)-O(6) bond length is 2.44 Å. The Ca(1)-O(7) bond length is 2.44 Å. The Ca(1)-O(8) bond length is 2.72 Å. There is one shorter (2.30 Å) and one longer (2.70 Å) Ca(1)-O(2) bond length. There is one shorter (2.34 Å) and one longer (2.62 Å) Ca(1)-O(3) bond length. There are five inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(3), one C(4), and one C(5) atom. The C(1)-C(3) bond length is 1.40 Å. The C(1)-C(4) bond length is 1.51 Å. The C(1)-C(5) bond length is 1.40 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one C(5), one O(2), and one O(3) atom. The C(2)-C(5) bond length is 1.50 Å. The C(2)-O(2) bond length is 1.26 Å. The C(2)-O(3) bond length is 1.27 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one C(1), one C(5), and one Br(1) atom. The C(3)-C(5) bond length is 1.40 Å. The C(3)-Br(1) bond length is 1.90 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(1), and one O(4) atom. The C(4)-O(1) bond length is 1.27 Å. The C(4)-O(4) bond length is 1.27 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one C(1), one C(2), and one C(3) atom. There are eight inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(5) atom. The H(1)-O(5) bond length is 0.99 Å. In the second H site, H(2) is bonded in a distorted linear geometry to one O(4) and one O(5) atom. The H(2)-O(4) bond length is 1.61 Å. The H(2)-O(5) bond length is 1.01 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(6) atom. The H(3)-O(6) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(6) atom. The H(4)-O(6) bond length is 0.98 Å. In the fifth H site, H(5) is bonded in a single-bond geometry to one O(7) atom. The H(5)-O(7) bond length is 0.98 Å. In the sixth H site, H(6) is bonded in a single-bond geometry to one O(7) atom. The H(6)-O(7) bond length is 0.99 Å. In the seventh H site, H(7) is bonded in a single-bond geometry to one O(8) atom. The H(7)-O(8) bond length is 0.99 Å. In the eighth H site, H(8) is bonded in a single-bond geometry to one O(8) atom. The H(8)-O(8) bond length is 1.00 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a single-bond geometry to one C(4) atom. In the second O site, O(2) is bonded in a 1-coordinate geometry to two equivalent Ca(1) and one C(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one C(4) and one H(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Ca(1), one H(1), and one H(2) atom. In the sixth O site, O(6) is bonded in a distorted water-like geometry to one Ca(1), one H(3), and one H(4) atom. In the seventh O site, O(7) is bonded in a distorted water-like geometry to one Ca(1), one H(5), and one H(6) atom. In the eighth O site, O(8) is bonded in a water-like geometry to one Ca(1), one H(7), and one H(8) atom. Br(1) is bonded in a single-bond geometry to one C(3) atom. Linkers: 1 [O]C(=O)c1c(Br)c(C([O])=O)c(C([O])=O)c(Br)c1C([O])=O. Metal clusters: 2 [Ca]. The MOF has largest included sphere 1.71 A, density 2.20 g/cm3, surface area 3070.89 m2/g, accessible volume 0.10 cm3/g