Unbiunium

Unbiunium, also known as eka-actinium or element 121, is a hypothetical <a href="/facts/Chemical_element/0jducgWD">chemical element</a>; it has <a href="/facts/Chemical_symbol/2Fe1VAL0">symbol</a> Ubu and <a href="/facts/Atomic_number/bgAr581S">atomic number</a> 121. Unbiunium and Ubu are the temporary <a href="/facts/Systematic_element_name/vJt86yzX">systematic IUPAC name and symbol</a> respectively, which are used until the element is discovered, confirmed, and a permanent name is decided upon. In the <a href="/facts/Periodic_table/umdGIfUb">periodic table</a> of the elements, it is expected to be the first of the <a href="/facts/Superactinide/Q3rg3qLA">superactinides</a>, and the third element in the eighth <a href="/facts/Period_(periodic_table)/WpGUFh5V">period</a>. It has attracted attention because of some predictions that it may be in the <a href="/facts/Island_of_stability/XuxQzqjL">island of stability</a>. It is also likely to be the first of a new <a href="/facts/Block_(periodic_table)/BbzD5jUU">g-block</a> of elements.
Unbiunium has not yet been synthesized. It is expected to be one of the last few reachable elements with current technology; the limit could be anywhere between element <a href="/facts/Unbinilium/gUvSSHzd">120</a> and <a href="/facts/Unbiquadium/2GXankKe">124</a>. It will also likely be far more difficult to synthesize than the elements known so far up to 118, and still more difficult than elements <a href="/facts/Ununennium/WnpMG7CP">119</a> and <a href="/facts/Unbinilium/gUvSSHzd">120</a>. The teams at <a href="/facts/RIKEN/dbVUF6zN">RIKEN</a> in Japan and at the <a href="/facts/JINR/JrSF8sQQ">JINR</a> in <a href="/facts/Dubna/mn37rc4l">Dubna</a>, Russia have indicated plans to attempt the synthesis of element 121 in the future after they attempt elements 119 and 120.
The position of unbiunium in the periodic table suggests that it would have similar properties to <a href="/facts/Lanthanum/Uhmmy1sB">lanthanum</a> and <a href="/facts/Actinium/GMQtJ4Gm">actinium</a>; however, <a href="/facts/Relativistic_quantum_chemistry/8A1se1CS">relativistic effects</a> may cause some of its properties to differ from those expected from a straight application of <a href="/facts/Periodic_trend/dI0mkSju">periodic trends</a>. For example, unbiunium is expected to have a s2p valence <a href="/facts/Electron_configuration/TQjRr22P">electron configuration</a>, instead of the s2d of lanthanum and actinium or the s2g expected from the <a href="/facts/Madelung_rule/GLqThvnE">Madelung rule</a>, but this is not predicted to affect its chemistry much. It would on the other hand significantly lower its first ionization energy beyond what would be expected from periodic trends.

Unbiunium open-in-new

Unbiunium