Polarized IR and Raman spectra of the novel metal-organic framework [CH3CH2NH3][Cd(HCOO)3]

The novel formate-based framework [CH3CH2NH3][Cd(HCOO)3] has been prepared under solvothermal conditions. The X-ray diffraction data reveals that this compound crystallizes in the polar Pna21 space group and is isostructural with the compounds [CH3CH2NH3][M(HCOO)3], where MII = Mg, Mn and Cu, reported previously. The ethylammonium cations located in the cavities of the metal-formate framework are ordered at room temperature. Polarized infrared and Raman spectra of [CH3CH2NH3][Cd(HCOO)3] single crystal have been measured at room temperature and the assignments of the observed bands to the respective external and internal vibrations are proposed. Additionally, the previously reported [CH3CH2NH3][Mn(HCOO)3] has also been synthesized and polycrystalline IR and Raman spectra of both metal-formate frameworks have been compared in order to better understand the aspects of their structures.