HomeJournal Of Research In Science, Computing And Engineeringvol. 4 no. 2 (2007)

The Crystal Structures of the Cu-M (M=Mn, Ca) Mixed Metal Formates: Their Multidimensional Polymeric Network Revisited

Julita C. Robles | Wyona C. Patalinghug

Discipline: Chemistry



The addition of a stoichiometric amount of the salt of the second metal (MnCl2 or CaCO3) to a solution of CuCO3·Cu(OH)2 in 20% formic acid produced a coordination polymer with two metal sites that are connected through a series of formate bridges. The analysis of the crystal structure of the compound, Cu0.94Mn1.06(HCOO)4·4H2O (1), reveals that it belongs to the monoclinic crystal system with the space group P21/c. The dimensions of the unit cell are a = 8.8241(18) Å, b = 7.1880(14) Å , c = 9.3405(19) Å, β= 97.24(3)°, and V = 587.7(2) Å3, while the results for the structure determination of Ca2Cu(HCOO)6 (cyrstal 2) shows that it belongs to the monoclinic space group, C2/c with the cell dimensions of a = 22.3524(45) Å, b = 8.7370(17) Å, c = 6.3200(13) Å, β = 101.462(39)°, and V = 1209.6(4) Å 3.The Cu-Mn mixed metal formate forms a two-dimensional network of Cu –OCO-Mn linkages with the Cu center surrounded with six formate ligands, while the Mn metal center exhibited a mixed coordination environment consisting of two formate ligands and 4 molecules of coordinated water. The Ca2Cu(HCOO)6(2) forms a multidimensional network of Cu-OCO-Ca linkages with the Cu center forming a hexaformate coordination environment while the Ca metal center is surrounded by seven formate ligands in a distorted pentagonal bipyramid structure.