Cr4Mn3(CO2)24 crystallizes in the trigonal R3c space group. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded in an octahedral geometry to one O(10), one O(13), one O(14), one O(7), one O(8), and one O(9) atom. The Cr(1)-O(10) bond length is 1.96 Å. The Cr(1)-O(13) bond length is 1.98 Å. The Cr(1)-O(14) bond length is 1.97 Å. The Cr(1)-O(7) bond length is 1.97 Å. The Cr(1)-O(8) bond length is 1.98 Å. The Cr(1)-O(9) bond length is 1.96 Å. In the second Cr site, Cr(2) is bonded in an octahedral geometry to three equivalent O(1) and three equivalent O(2) atoms. All Cr(2)-O(1) bond lengths are 1.99 Å. All Cr(2)-O(2) bond lengths are 1.97 Å. Mn(1) is bonded in a 8-coordinate geometry to one O(11), one O(12), one O(15), one O(16), one O(3), one O(4), one O(5), and one O(6) atom. The Mn(1)-O(11) bond length is 2.18 Å. The Mn(1)-O(12) bond length is 2.66 Å. The Mn(1)-O(15) bond length is 2.23 Å. The Mn(1)-O(16) bond length is 2.41 Å. The Mn(1)-O(3) bond length is 2.30 Å. The Mn(1)-O(4) bond length is 2.37 Å. The Mn(1)-O(5) bond length is 2.41 Å. The Mn(1)-O(6) bond length is 2.25 Å. There are eight inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(1) and one O(3) atom. The C(1)-O(1) bond length is 1.28 Å. The C(1)-O(3) bond length is 1.23 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(2) and one O(4) atom. The C(2)-O(2) bond length is 1.29 Å. The C(2)-O(4) bond length is 1.22 Å. In the third C site, C(3) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(7) atom. The C(3)-O(5) bond length is 1.22 Å. The C(3)-O(7) bond length is 1.26 Å. In the fourth C site, C(4) is bonded in a distorted bent 120 degrees geometry to one O(6) and one O(8) atom. The C(4)-O(6) bond length is 1.21 Å. The C(4)-O(8) bond length is 1.26 Å. In the fifth C site, C(5) is bonded in a distorted bent 120 degrees geometry to one O(10) and one O(11) atom. The C(5)-O(10) bond length is 1.25 Å. The C(5)-O(11) bond length is 1.24 Å. In the sixth C site, C(6) is bonded in a distorted bent 120 degrees geometry to one O(12) and one O(9) atom. The C(6)-O(12) bond length is 1.22 Å. The C(6)-O(9) bond length is 1.27 Å. In the seventh C site, C(7) is bonded in a distorted bent 120 degrees geometry to one O(13) and one O(15) atom. The C(7)-O(13) bond length is 1.25 Å. The C(7)-O(15) bond length is 1.22 Å. In the eighth C site, C(8) is bonded in a distorted bent 120 degrees geometry to one O(14) and one O(16) atom. The C(8)-O(14) bond length is 1.28 Å. The C(8)-O(16) bond length is 1.23 Å. There are sixteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Cr(2) and one C(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Cr(2) and one C(2) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Mn(1) and one C(1) atom. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Mn(1) and one C(2) atom. In the fifth O site, O(5) is bonded in a distorted water-like geometry to one Mn(1) and one C(3) atom. In the sixth O site, O(6) is bonded in a bent 120 degrees geometry to one Mn(1) and one C(4) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Cr(1) and one C(3) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Cr(1) and one C(4) atom. In the ninth O site, O(9) is bonded in a bent 120 degrees geometry to one Cr(1) and one C(6) atom. In the tenth O site, O(10) is bonded in a bent 120 degrees geometry to one Cr(1) and one C(5) atom. In the eleventh O site, O(11) is bonded in a bent 120 degrees geometry to one Mn(1) and one C(5) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to one Mn(1) and one C(6) atom. In the thirteenth O site, O(13) is bonded in a bent 120 degrees geometry to one Cr(1) and one C(7) atom. In the fourteenth O site, O(14) is bonded in a bent 120 degrees geometry to one Cr(1) and one C(8) atom. In the fifteenth O site, O(15) is bonded in a bent 120 degrees geometry to one Mn(1) and one C(7) atom. In the sixteenth O site, O(16) is bonded in a distorted water-like geometry to one Mn(1) and one C(8) atom. Linkers: 72 [O]C(=O)C([O])=O. Metal clusters: 18 [Mn] ,24 [Cr]. The MOF has largest included sphere 7.05 A, density 1.02 g/cm3, surface area 3171.55 m2/g, accessible volume 0.66 cm3/g