Experimental (FT-IR and FT-RS) and theoretical (DFT) studies of molecular structure and internal modes of [Mn(NH3)6](NO3)2.

Abstract Fourier-transform Raman and infrared spectra of [Mn(NH 3 ) 6 ](NO 3 ) 2 were recorded and interpreted by comparison with respective theoretical spectra calculated using DFT method. The [Mn(NH 3 ) 6 ] 2+ cation equilibrium geometry with C 1 symmetry, harmonic vibrational frequencies, infrared and Raman scattering intensities were determined using B3LYP/LAN2LTZ+/6-311+G(d,p) level of theory. The band assignment was based on potential energy distribution (PED) of normal modes. The computations of NO 3 − anion frequencies were performed under assumption of D 3 h symmetry, using 6-311+G(d,p) basis set. In order do draw a comparison, additional calculations were performed separately for the [Cd(NH 3 ) 6 ](NO 3 ) 2 and [Ni(NH 3 ) 6 ](NO 3 ) 2 . The computations were also carried out using selected modern exchange-correlation functionals. A sufficient general agreement between the theoretical and the experimental spectra has been achieved.