 Several experiments have been performed between 2000 and 2004 at the Flerov Laboratory of Nuclear Reactions in Dubna studying the fission characteristics of the compound nucleus <unk> by bombarding a plutonium @-@ 244 target with accelerated calcium @-@ 48 ions . A compound nucleus is a loose combination of nucleons that have not yet arranged themselves into nuclear shells . It has no internal structure and is held together only by the collision forces between the target and projectile nuclei . The results revealed how nuclei such as this fission predominantly by expelling doubly magic or nearly doubly magic fragments such as calcium @-@ 40 , tin @-@ 132 , lead @-@ 208 , or bismuth @-@ 209 . It was also found that the yield for the fusion @-@ fission pathway was similar between calcium @-@ 48 and iron @-@ 58 projectiles , indicating a possible future use of iron @-@ 58 projectiles in superheavy element formation . It has also been suggested that a neutron @-@ rich flerovium isotope can be formed by the quasifission ( partial fusion followed by fission ) of a massive nucleus . Recently it has been shown that the multi @-@ nucleon transfer reactions in collisions of actinide nuclei ( such as uranium and curium ) might be used to synthesize the neutron @-@ rich superheavy nuclei located at the island of stability , although production of neutron @-@ rich nobelium or seaborgium nuclei is more likely . 
