263-106---a--->259-104---a--->255No---a--->

The Dubna Team, directed by Flerov and Organessian, produced heavy ions of 54Cr with their 310-cm heavy-ion cyclotron to bombard 207Pb and 208Pb and found a product that decayed with a half-life of 7 ms. They assigned 259-106 to this isotope. Earlier, the IUPAC proposed a temporary name of unnilhexium for this element. The Berkeley Group, who first claimed positive identification, proposed the name seaborgium to Element 106. In 1994 the IUPAC recommended the name rutherfordium with the symbol Rf to this element; however, this name is being challenged by the Berkeley Group. The name rutherfordium has been used for many year for Element 104, which would lead to confusion if the name for Element 104 is changed. The naming of this element is now unsettled. It is now thought six isotopes of Element 106 have been identified. Two of the isotopes are believed to have half-lives of about 30 s.