Spectroscopic properties of guanidinium zinc sulphate [C(NH2)3]2Zn(SO4)2 and ab initio calculations of [C(NH2)3]2 and HC(NH2)3

Raman and FTIR spectra of guanidinium zinc sulphate [C(NH2)3]2Zn(SO4)2 are recorded and the spectral bands assignment is carried out in terms of the fundamental modes of vibration of the guanidinium cations and sulphate anions. The analysis of the spectrum reveals distorted SO42− tetrahedra with distinct S–O bonds. The distortion of the sulphate tetrahedra is attributed to Zn–O–S–O–Zn bridging in the structure as well as hydrogen bonding. The CN3 group is planar which is expressed in the twofold symmetry along the C–N (1) vector. Spectral studies also reveal the presence of hydrogen bonds in the sample. The vibrational frequencies of [C(NH2)3]2 and HC(NH2)3 are computed using Gaussian 03 with HF/6-31G* as basis set.