ISSN:
1588-2780
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract Four types of neptunyl(VI) hydroxides have been synthesized by chemical oxidation of Np(IV) instead of ozone oxidation of Np(V) which caused the partial oxidation to the heptavalent state. NpO2(OH)2 (I) and NpO2(OH)2·H2O (orthorhombic type) (II) have been obtained by adding pyridine to the solution at 373K and 343K, respectively. NpO2(OH)2·H2O (hexagonal type) (III) and NpO2(OH)2·xH2O·yNH3 (x+y=1) (IV) have been prepared by using LiOH and NH4OH, respectively. The four materials have been characterized by X-ray powder diffraction patterns, thermogravimetric analysis and237Np Mössbauer spectra. The237Np Mössbauer spectrum of (I) measured first time as anhydrous neptunyl(VI) hydroxide (δ=−46.2 mm/s,e 2 qQ=193 mm/s and η=0.16 at 4.8K) has more distinct five-line Mössbauer pattern than those of (II), (III) and (IV). The Mössbauer spectra for (II), (III) and (IV) are slightly different from each other. The structural information has been obtained from these data.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02349504
Permalink