Ununseptium is the temporary name of the chemical element with temporary symbol Uus and atomic number 117. Six atoms were detected by a joint Russia–US collaboration at Dubna, Moscow Oblast, Russia, in 2009–10 Although it is currently placed as the heaviest member of the halogen family, there is no experimental evidence that the chemical properties of ununseptium match those of the lighter members like iodine or astatine and theoretical analysis suggests there may be some notable differences. In January 2010, scientists at the Flerov Laboratory of Nuclear Reactions announced internally that they had succeeded in detecting the decay of a new element with Z=117 using the reactions: 48 20Ca + 249 97Bk → 297 117Uus* → 294 117Uus + 3 1 0n 48 20Ca + 249 97Bk → 297 117Uus* → 293 117Uus + 4 1 0n