Divalent ions in aqueous solution

Yu, H., et al.. Simulating monovalent and divalent ions in aqueous solution using a Drude polarizable force field./. Chem. Theory Comput, 2010. 6[3], 774-786. 

Because No is normally a divalent ion in aqueous solution and is difficult to oxidize and hold in the trivalent state, it has not been possible to make a chemical identification of the atomic number in the same manner as the preceding 3 -i-actinides, i.e. identification by their unique positions in the elution sequence from cation-exchange resin columns. However, in 1971, the atomic number of No was unequivocally determined through the observation of characteristic K-series x-rays of the daughter isotope Fm in coincidence with the alpha particles from the decay of the parent, No [10]. 

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