belaruksiin
Belaruksiin is a proposed, hypothetical element with the symbol Brx and atomic number 133. It is positioned within the superactinide series, which represents theoretical elements beyond the currently known actinide series in the periodic table. As a superactinide, belaruksiin would be expected to possess properties influenced by the filling of the 5g electron subshell, a region not occupied by electrons in any elements found naturally or synthesized thus far.
The existence of belaruksiin has not been experimentally confirmed, and its properties are largely theoretical, extrapolated