Ununoctium is the provisional name for the transuranic element (i.e. heavier than uranium) 118 of atomic mass 294. Chemical symbol Uuo. Its chemical properties, which have never been observed, should be similar to those of radon. In 1999 the team of Victor Ninov (Lawrence Berkeley National Laboratory, California) announced that it had been synthesised, but the claim has since been withdrawn. Its synthesis was again announced in October 2006 by a group composed of the team of Yuri Oganessian of the Dubna nuclear research Institute (Russia) and a team from Lawrence Livermore National Laboratory (California).