MnH3(CO2)3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded in an octahedral geometry to one O(1), one O(11), one O(3), one O(4), one O(6), and one O(8) atom. The Mn(1)-O(1) bond length is 2.14 Å. The Mn(1)-O(11) bond length is 2.15 Å. The Mn(1)-O(3) bond length is 2.18 Å. The Mn(1)-O(4) bond length is 2.17 Å. The Mn(1)-O(6) bond length is 2.19 Å. The Mn(1)-O(8) bond length is 2.18 Å. In the second Mn site, Mn(2) is bonded in an octahedral geometry to one O(10), one O(12), one O(2), one O(5), one O(7), and one O(9) atom. The Mn(2)-O(10) bond length is 2.15 Å. The Mn(2)-O(12) bond length is 2.18 Å. The Mn(2)-O(2) bond length is 2.20 Å. The Mn(2)-O(5) bond length is 2.14 Å. The Mn(2)-O(7) bond length is 2.15 Å. The Mn(2)-O(9) bond length is 2.16 Å. There are six inequivalent C sites. In the first C site, C(1) is bonded in a trigonal planar geometry to one H(5), one O(12), and one O(8) atom. The C(1)-H(5) bond length is 0.97 Å. The C(1)-O(12) bond length is 1.22 Å. The C(1)-O(8) bond length is 1.25 Å. In the second C site, C(2) is bonded in a trigonal planar geometry to one H(6), one O(3), and one O(7) atom. The C(2)-H(6) bond length is 0.98 Å. The C(2)-O(3) bond length is 1.24 Å. The C(2)-O(7) bond length is 1.23 Å. In the third C site, C(3) is bonded in a trigonal planar geometry to one H(1), one O(6), and one O(9) atom. The C(3)-H(1) bond length is 0.95 Å. The C(3)-O(6) bond length is 1.24 Å. The C(3)-O(9) bond length is 1.22 Å. In the fourth C site, C(4) is bonded in a trigonal planar geometry to one H(2), one O(10), and one O(11) atom. The C(4)-H(2) bond length is 0.85 Å. The C(4)-O(10) bond length is 1.22 Å. The C(4)-O(11) bond length is 1.23 Å. In the fifth C site, C(5) is bonded in a trigonal planar geometry to one H(3), one O(2), and one O(4) atom. The C(5)-H(3) bond length is 1.00 Å. The C(5)-O(2) bond length is 1.24 Å. The C(5)-O(4) bond length is 1.23 Å. In the sixth C site, C(6) is bonded in a trigonal planar geometry to one H(4), one O(1), and one O(5) atom. The C(6)-H(4) bond length is 1.03 Å. The C(6)-O(1) bond length is 1.20 Å. The C(6)-O(5) bond length is 1.23 Å. There are six 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(4) atom. In the third H site, H(3) is bonded in a single-bond geometry to one C(5) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one C(6) atom. In the fifth H site, H(5) is bonded in a single-bond geometry to one C(1) atom. In the sixth H site, H(6) is bonded in a single-bond geometry to one C(2) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Mn(1) and one C(6) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Mn(2) and one C(5) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Mn(1) and one C(2) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Mn(1) and one C(5) atom. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one C(6) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one Mn(1) and one C(3) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Mn(2) and one C(2) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Mn(1) and one C(1) atom. In the ninth O site, O(9) is bonded in a bent 150 degrees geometry to one Mn(2) and one C(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Mn(2) and one C(4) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Mn(1) and one C(4) atom. In the twelfth O site, O(12) is bonded in a distorted bent 150 degrees geometry to one Mn(2) and one C(1) atom. Linkers: 24 [O]C=O. Metal clusters: 8 [Mn]. The MOF has largest included sphere 4.71 A, density 1.29 g/cm3, surface area 4028.03 m2/g, accessible volume 0.40 cm3/g