Raman and infrared spectral studies of [C(NH2)3]2MII(H2O)4(SO4)2, MII = Mn, Cd and VO

Abstract The Raman and FTIR spectra of three metal guanidinium sulfates, [C(NH 2 ) 3 ] 2 M II (H 2 O) 4 (SO 4 ) 2 , (M II = Mn, Cd and VO), are recorded. The observed spectral bands are assigned in terms of the fundamental modes of vibration of the guanidinium ions, sulfate groups and water molecules. The appearance of the sulfate tetrahedra's ν 1 and ν 2 modes in the IR spectra and the partial lifting of the ν 4 mode in the Raman spectra indicate the distortion of the SO 4 2− tetrahedra in the structure, so that its symmetry is lowered from T d to C 1 . The geometry of the sulfate group in guanidinium vanadyl sulfate does not deviate much from that of the average sulfate group. The distortion of the SO 4 tetrahedra is stronger in GuCds than in GuMnS. The CN 3 group in the guanidinium ion is planar ( D 3 h point group) in GuCdS and GuMnS, whereas it is lowered in the vanadyl compound. Furthermore, the spectral analyses show the presence of weak hydrogen bonds in the structures. Copyright © 2007 John Wiley & Sons, Ltd.