Unbioctium
{{Redirect category shell|1= Unbioctium, also known as element 128 or eka-curium, is the hypothetical chemical element with atomic number 128 and placeholder symbol Ubo. Unbioctium and Ubo are the temporary IUPAC name and symbol, respectively, until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table, unbioctium is expected to be a g-block superactinide and the eighth element in the 8th period. Unbioctium has attracted attention among nuclear physicists, especially in early predictions targeting properties of superheavy elements, for 128 may be a magic number of protons near the center of an island of stability, leading to longer half-lives, especially for 318Ubo or 358Ubo which may also have magic numbers of neutrons.[1]
Early interest in possible increased stability led to the first attempted synthesis of unbioctium in 1999 and searches for it in nature in subsequent years. Despite several reported observations, more recent studies suggest that these experiments were insufficiently sensitive; hence, no Unbioctium has been found naturally or artificially.[2] Predictions of the stability of unbioctium vary greatly among different models; some suggest the island of stability may instead lie at a lower atomic number, closer to oganesson and thulium. Unbioctium is predicted to be a chemically active superactinide, exhibiting a variety of oxidation states from +1 to +8, and possibly being a heavier congener of curium. It is predicted to be the fourth element with an electron in a g orbital, a consequence of relativistic effects seen only in heavy and superheavy elements. An overlap in energy levels of the 5g, 6f, 7d, and 8p orbitals is also expected, which complicates predictions of chemical properties for this element.