Unbiunium

Unbiunium is a hypothetical (theoretical or imagined) element of the periodic table. It is also known as eka-actinium or dvi-lanthanum.
Its atomic number should be 121 and it has the symbol Ubu. The name Unbiunium and the symbol Ubu are temporary IUPAC names (meaning "one-two-one" in Latin). This name and symbol exist until a permanent name is decided and the element is created. It is expected to be a F-block element and in a group call the superactinides  or Unbiunoids. It is the third element in the eighth period of the periodic table.

 Creation attempts 
The synthesis of unbiunium was first attempted in 1977 by bombarding a target of uranium-238 with copper-65 ions at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany:
 238U + 65Cu → 303Ubu
No atoms were identified.

Another alternative name is "Lavoisium".

References

Category:Hypothetical chemical elements
Category:Superactinides