Vibrational Spectra of Anhydrous Lanthanum, Europium, Gadolinium, and Dysprosium Nitrates and Oxinitrates

Abstract

IR. and Raman spectra of LnONO₃ (50–4,000 cm⁻¹, LnLa, Gd, Eu, and Dy) are reported and discussed. The low frequency region of the spectra reflects the cubic structure of these compounds. The dimensions of the cubic unit cells determined by X‐Ray powder diagrams are: 12.81 ± 0.05 Å for EuONO₃, 12.69 ± 0.05 Å for GdONO₃, and 12.67 ± 0.05 Å for DyONO₃. The vibrational frequencies of the nitrato group are consistent with a bidentate nitrate of C_2v symmetry. The synthesis of anhydrous Ln (NO₃)₃ (LnLa, Gd, Eu, and Dy) by dehydration of the corresponding penta‐ or hexahydrates is described. The IR. and Raman spectra (50‐4,000 cm⁻¹) are analysed. Splitting of the bands point to a complex structure of these compounds. All six vibrational modes of the nitrato group are observed and the data are again consistent with bidentate NO⁻₃ moieties. Finally, an analytical control of the purity of Ln (NO₃)₃ is suggested.