Symmetry, Optical Properties and Thermodynamics of Neptunium(V) Complexes

Linfeng Rao,Guoxin Tian

doi:10.3390/sym2010001

Abstract

Recent results on the optical absorption and symmetry of the Np(V) complexes with dicarboxylate and diamide ligands are reviewed. The importance of recognizing the “silent” feature of centrosymmetric Np(V) species in analyzing the absorption spectra and calculating the thermodynamic constants of Np(V) complexes is emphasized.

Highlights

Neptunium, an element in the actinide series of the periodic table, has an electronic configuration of [Rn]5f57s2
As the concentration of ODA was further increased (Phase II), the intensities at 989 and 1035 nm started to decrease but no new absorption peaks appeared at longer wavelengths. These changes in the spectra are different from those for the NpO2+ complexation with oxalate (Figure 2) where the decrease of the absorbance of the first complex is accompanied by the appearance of new absorption band(s) of successive complexes at longer wavelengths
In a recent spectrophotometric study of the complexation of Np(V) with Methyliminodiacetic Acid (MIDA) in the aqueous solution, spectra changes similar to those in the Np(V)/Dipicolinic Acid (DPA) system were observed and interpreted with the successive formation of NpO2(MIDA)- and NpO2(MIDA)23, the latter not absorbing in the near-IR region because it is centrosymmetric [32]

Summary

Introduction

An element in the actinide series of the periodic table, has an electronic configuration of [Rn]5f57s2 (or [Rn]5f46d17s2). If the Np(V) complex is centrosymmetric and the neptunium atom is at the inversion center, the f-f transitions of Np(V) are forbidden and the near-IR absorption bands will be “silent”.

Results

Conclusion