This prompted further exploration of the chemical behavior of complexes of dubnium. This greatly limits the extent of research on dubnium. A limited investigation of dubnium chemistry has confirmed this. There are exceptions, however, including several isotopes of curium and dubnium. Eka-tantalum is actually the synthetic superheavy element dubnium (105). Thus, IUPAC reconsidered, and in 1996 named element 105 dubnium and element 106 seaborgium. Experimental results of the chemistry of dubnium date back to 1974 and 1976. Es (einsteinium) or Db (dubnium), respectively. The short half-life of dubnium limits experimentation. The name "dubnium" was given to element 105 at the same time. The next studies on the chemistry of dubnium were conducted in 1988, in Berkeley. The name "dubnium" had been used for element 104 in the previous IUPAC recommendation. They examined whether the most stable oxidation state of dubnium in aqueous solution was +5. Group 5 contains vanadium (V), niobium (Nb), tantalum (Ta) and dubnium (Db). The Americans wished to name element 105 hahnium, while the Russians preferred the name dubnium.