Neglected solid phase pentavalent plutonium carbonate in the environment

KPuO 2 CO 3 solid phase precipitation from hexavalent plutonium (Pu( vi )) solution is discussed herein. The kinetic process of Pu( v )/potassium carbonate formation is widely investigated under constant control of Pu concentration in different oxidation states, redox potentials, and pH values. Synchrotron-based X-ray diffraction, X-ray absorption spectroscopy, high-resolution transmission electron microscopy, and scanning electron microscopy with energy-dispersive X-ray spectroscopy are employed for solid phase analysis. The crystal structure of KPuO 2 CO 3 is specified via the Rietveld method and extended X-ray absorption fine structure fitting. The stability area of Pu( v ) potassium carbonate is discussed and a moderated Pourbaix diagram is presented.