Unbiunium is a hypothetical (theoretical or imagined) element of the periodic table. It is also known as eka-actinium. The atomic number of this element is 121. It has the symbol Ubu. The name Unbiunium and the symbol Ubu are temporary IUPAC names. This name and symbol exist until a permanent name is decided. It is expected to be a F-block element and an superactinides. It is the third element in the eighth period of the periodic table.
- 238U + 65Cu → 303Ubu
No atoms were identified.