A NEW SIMPLE ROUTE FOR SYNTHESIS OF CADMIUM(II), ZINC(II), COBALT(II), AND MANGANESE(II) CARBONATES USING UREA AS A CHEAP PRECURSOR AND THEORETICAL INVESTIGATION

Abstract

The MnCO3.H2O, CoCO3.4H2O, ZnCO3, and CdCO3, respectively, were synthesized through a new precise, easy pathway for the reaction of MnI2, CoI2, ZnI2, or CdI2 aqueous solutions with a cheap precursor-urea for 10 h at ~ 70 oC. The IR spectra of reaction products designate the presence of characteristic bands of ionic carbonate, CO32– and absence of the individual bands of urea. The (CO3)2- ion is planar and therefore, it belongs to the D3h symmetry. It is expected to display four modes of vibrations. The stretching vibrations of the type; ν(C-O) is observed in the range of (1376-1503) cm-1 while another stretching vibration ν(C-O) is observed in the region 1060-1079 cm-1. The out of plane of vibration δ(OCO) is observed in the range of (833-866) cm-1 while, the angle deformation bending vibration δ(OCO) appear in the range of (708-732) cm-1. The infrared spectra of metal carbonate, show that, this product clearly has an uncoordinated water. The band related to the stretching vibration ν(O-H) of uncoordinated H2O is observed as expected in the range of ~ 3000 cm-1. A general mechanism explaining the synthesis of carbonate compounds of cadmium(II), zinc(II), cobalt(II), and manganese(II), are described. Moreover, the DFT outcomes using B3LYP/LanL2DZ (basis set) agree with the experimental results.