Further insights into intermediate- and mixed-valency in neptunium oxoanion compounds: structure and absorption spectroscopy of K2[(NpO2)3B10O16(OH)2(NO3)2]Electronic supplementary information (ESI) available: CIF file for K2[(NpO2)3B10O16(OH)2(NO3)2]. 237Np (t1/2= 2.14 × 106y) represents a serious health risk owing to its α and γ emission. All studies with neptunium and were conducted in a lab dedicated to studies on transuranium elements. CCDC 765550. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c002588g

The reaction of Np(v) chloride with molten boric acid results in the disproportionation of Np(v) into Np(iv) and Np(vi), and the crystallization of K2[(NpO2)3B10O16(OH)2(NO3)2]. UV-vis-NIR spectroscopy demonstrates that in addition to the Np(vi) and Np(v) found in the crystal structure, Np(iv) is also present. [ABSTRACT FROM AUTHOR]