What is "unbinilium"

n. The systematic element name for the (as yet undiscovered) chemical element with atomic number 120 (''symbol'' Ubn).

Unbinilium, also known as eka- radium or simply element 120, is the hypothetical chemical element in the periodic table with atomic number 120 and symbol Ubn. 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.

Unbinilium has not yet been synthesized, despite multiple attempts from German and Russian teams. Experimental evidence from these attempts show that the period 8 elements will likely be far more difficult to synthesise than the previous known elements, and that unbinilium may even be the last element that can be synthesized with current technology. Its position as the seventh alkaline earth metal suggests that it would have similar properties to its lighter congeners, beryllium, magnesium, calcium, strontium, barium, and radium; however, relativistic effects may cause some of its properties to differ from those expected from a straight application of periodic trends. For example, unbinilium is expected to be less reactive than barium and radium and be closer in behavior to strontium, and while it should show the characteristic +2 oxidation state of the alkaline earth metals, it is also predicted to show the +4 oxidation state unknown in any other alkaline earth metal.