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Unbiunium (pronounced /uːnbaɪˈuːniəm/) is the temporary name of a hypothetical chemical element in the periodic table that has the temporary symbol Ubu and has the atomic number 121.

Unbiunium is the first element whose ground state electron configuration contains an electron in a g subshell, making it the first element in the g-block. However, neither lanthanum nor actinium show such a predicted ground state for the f-block, and lie in the transition metals, so unbiunium's third electron should also hang up. Other elements have access to their g subshells, though not in their ground states. Calculations have shown that 320Ubu would be the most stable isotope.

As of November 2009, no attempt has ever been made to synthesize unbiunium.

Naming

The name unbiunium is a systematic element name, used as a placeholder until it is confirmed by other research groups and the IUPAC decides on a name. Usually, the name suggested by the discoverer(s) is chosen.
Target-projectile combinations leading to Z=121 compound nuclei

The below table contains various combinations of targets and projectiles which could hypothetically be used to form compound nuclei with atomic number 121.

g to Z=121 nuclei
Target Projectile CN Attempt result
208Pb 89Y 297Ubu Reaction yet to be attempted
232Th 71Ga 303Ubu Reaction yet to be attempted
238U 65Cu 303Ubu Reaction yet to be attempted
237Np 64Ni 301Ubu Reaction yet to be attempted
244Pu 59Co 303Ubu Reaction yet to be attempted
243Am 58Fe 301Ubu Reaction yet to be attempted
248Cm 55Mn 303Ubu Reaction yet to be attempted
249Bk 54Cr 303Ubu Reaction yet to be attempted
249Cf 51V 300Ubu Reaction yet to be attempted
254Es 50Ti 304Ubu Reaction yet to be attempted


External links

* Journal of Chemical Physics, 1998, V 109, N 10, 8 Sep.

Chemistry Encyclopedia

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