CaC7NH3O4 crystallizes in the triclinic P-1 space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one N(1), one O(11), one O(2), one O(7), and two equivalent O(3) atoms. The Ca(1)-N(1) bond length is 2.56 Å. The Ca(1)-O(11) bond length is 2.47 Å. The Ca(1)-O(2) bond length is 2.29 Å. The Ca(1)-O(7) bond length is 2.26 Å. There is one shorter (2.39 Å) and one longer (2.57 Å) Ca(1)-O(3) bond length. In the second Ca site, Ca(2) is bonded in a distorted square pyramidal geometry to one N(2), one O(1), one O(10), one O(12), and one O(4) atom. The Ca(2)-N(2) bond length is 2.49 Å. The Ca(2)-O(1) bond length is 2.30 Å. The Ca(2)-O(10) bond length is 2.27 Å. The Ca(2)-O(12) bond length is 2.28 Å. The Ca(2)-O(4) bond length is 2.29 Å. In the third Ca site, Ca(3) is bonded in a square co-planar geometry to two equivalent O(5) and two equivalent O(8) atoms. Both Ca(3)-O(5) bond lengths are 2.36 Å. Both Ca(3)-O(8) bond lengths are 2.31 Å. In the fourth Ca site, Ca(4) is bonded in a square co-planar geometry to two equivalent O(6) and two equivalent O(9) atoms. Both Ca(4)-O(6) bond lengths are 2.30 Å. Both Ca(4)-O(9) bond lengths are 2.37 Å. There are twenty-one inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one C(15), one C(3), and one C(8) atom. The C(1)-C(15) bond length is 1.51 Å. The C(1)-C(3) bond length is 1.39 Å. The C(1)-C(8) bond length is 1.39 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one C(18), one C(7), and one C(8) atom. The C(2)-C(18) bond length is 1.52 Å. The C(2)-C(7) bond length is 1.39 Å. The C(2)-C(8) bond length is 1.39 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one C(1), one N(1), and one H(1) atom. The C(3)-N(1) bond length is 1.34 Å. The C(3)-H(1) bond length is 0.93 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one C(14), one C(17), and one C(5) atom. The C(4)-C(14) bond length is 1.38 Å. The C(4)-C(17) bond length is 1.50 Å. The C(4)-C(5) bond length is 1.38 Å. In the fifth C site, C(5) is bonded in a single-bond geometry to one C(4), one C(6), and one H(2) atom. The C(5)-C(6) bond length is 1.38 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(13), one C(5), and one C(9) atom. The C(6)-C(13) bond length is 1.39 Å. The C(6)-C(9) bond length is 1.50 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one C(2), one N(1), and one H(3) atom. The C(7)-N(1) bond length is 1.34 Å. The C(7)-H(3) bond length is 0.93 Å. In the eighth C site, C(8) is bonded in a distorted single-bond geometry to one C(1), one C(2), and one H(4) atom. The C(8)-H(4) bond length is 0.93 Å. In the ninth C site, C(9) is bonded in a distorted bent 120 degrees geometry to one C(6), one O(2), and one O(8) atom. The C(9)-O(2) bond length is 1.25 Å. The C(9)-O(8) bond length is 1.24 Å. In the tenth C site, C(10) is bonded in a bent 120 degrees geometry to one C(12), one O(11), and one O(3) atom. The C(10)-C(12) bond length is 1.50 Å. The C(10)-O(11) bond length is 1.24 Å. The C(10)-O(3) bond length is 1.26 Å. In the eleventh C site, C(11) is bonded in a trigonal planar geometry to one C(16), one C(19), and one C(20) atom. The C(11)-C(16) bond length is 1.50 Å. The C(11)-C(19) bond length is 1.39 Å. The C(11)-C(20) bond length is 1.38 Å. In the twelfth C site, C(12) is bonded in a trigonal planar geometry to one C(10), one C(19), and one C(21) atom. The C(12)-C(19) bond length is 1.39 Å. The C(12)-C(21) bond length is 1.39 Å. In the thirteenth C site, C(13) is bonded in a distorted trigonal planar geometry to one C(6), one N(2), and one H(5) atom. The C(13)-N(2) bond length is 1.34 Å. The C(13)-H(5) bond length is 0.93 Å. In the fourteenth C site, C(14) is bonded in a distorted bent 120 degrees geometry to one C(4), one N(2), and one H(6) atom. The C(14)-N(2) bond length is 1.34 Å. The C(14)-H(6) bond length is 0.93 Å. In the fifteenth C site, C(15) is bonded in a distorted bent 120 degrees geometry to one C(1), one O(4), and one O(5) atom. The C(15)-O(4) bond length is 1.25 Å. The C(15)-O(5) bond length is 1.25 Å. In the sixteenth C site, C(16) is bonded in a distorted bent 120 degrees geometry to one C(11), one O(10), and one O(12) atom. The C(16)-O(10) bond length is 1.24 Å. The C(16)-O(12) bond length is 1.25 Å. In the seventeenth C site, C(17) is bonded in a distorted bent 120 degrees geometry to one C(4), one O(6), and one O(7) atom. The C(17)-O(6) bond length is 1.24 Å. The C(17)-O(7) bond length is 1.24 Å. In the eighteenth C site, C(18) is bonded in a distorted bent 120 degrees geometry to one C(2), one O(1), and one O(9) atom. The C(18)-O(1) bond length is 1.25 Å. The C(18)-O(9) bond length is 1.25 Å. In the nineteenth C site, C(19) is bonded in a distorted single-bond geometry to one C(11), one C(12), and one H(7) atom. The C(19)-H(7) bond length is 0.93 Å. In the twentieth C site, C(20) is bonded in a distorted trigonal planar geometry to one C(11), one N(3), and one H(8) atom. The C(20)-N(3) bond length is 1.34 Å. The C(20)-H(8) bond length is 0.93 Å. In the twenty-first C site, C(21) is bonded in a distorted bent 120 degrees geometry to one C(12), one N(3), and one H(9) atom. The C(21)-N(3) bond length is 1.34 Å. The C(21)-H(9) bond length is 0.93 Å. There are three inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one Ca(1), one C(3), and one C(7) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one Ca(2), one C(13), and one C(14) atom. In the third N site, N(3) is bonded in a bent 120 degrees geometry to one C(20) and one C(21) atom. There are nine inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one C(3) 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(7) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(8) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(13) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(14) atom. In the seventh H site, H(7) is bonded in a single-bond geometry to one C(19) atom. In the eighth H site, H(8) is bonded in a single-bond geometry to one C(20) atom. In the ninth H site, H(9) is bonded in a single-bond geometry to one C(21) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ca(2) and one C(18) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one C(9) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent Ca(1) and one C(10) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Ca(2) and one C(15) atom. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ca(3) and one C(15) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Ca(4) and one C(17) atom. In the seventh O site, O(7) is bonded in a linear geometry to one Ca(1) and one C(17) atom. In the eighth O site, O(8) is bonded in a distorted linear geometry to one Ca(3) and one C(9) atom. In the ninth O site, O(9) is bonded in a linear geometry to one Ca(4) and one C(18) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Ca(2) and one C(16) atom. In the eleventh O site, O(11) is bonded in an L-shaped geometry to one Ca(1) and one C(10) atom. In the twelfth O site, O(12) is bonded in a bent 150 degrees geometry to one Ca(2) and one C(16) atom. Linkers: 6 [O]C(=O)c1cncc(C([O])=O)c1. Metal clusters: 6 [Ca]. The MOF has largest included sphere 5.92 A, density 0.98 g/cm3, surface area 4009.30 m2/g, accessible volume 0.62 cm3/g