Ubn的中子数为幻数，根据稳定岛理论推测其半衰期极长。

2002年，尤里·奥加涅相在俄罗斯杜布纳的团队于联合核研究所（JINR）首次发现并观测Uuo原子的衰变， 之后打算制作类似的实验：从Fe和Pu制造Ubn。 Ubn同位素的半衰期预计以微秒计。

Unbinilium /uːnbaɪˈnɪliəm/, also known as eka-radium or simply element 120, is the temporary, systematic element name of a hypothetical chemical element in the periodic table with the temporary symbol Ubn and the atomic number 120. Unbinilium and Ubn are the temporary systematic IUPAC name and symbol, until a permanent name is decided upon. In the periodic table of the elements, it is expected to be an s-block element, an alkaline earth metal, and the second element in the eighth period.