 In March 1999 , the same team replaced the 244Pu target with a 242Pu one in order to produce other flerovium isotopes . This time two atoms of flerovium were produced , decaying via alpha emission with a half @-@ life of 5 @.@ 5 s . They were assigned as 287Fl . This activity has not been seen again either , and it is unclear what nucleus was produced . It is possible that it was the meta @-@ stable isomer 287mFl . 
