unbibium, also known as element 122 or eka-thorium, is the possible chemical element in the periodic table with the placeholder symbol of ubb and atomic number 122. "unbibium" and "ubb" are the temporary systematic iupac name and symbol, which are used until the element is discovered, confirmed, and a permanent name is decided upon. in the periodic table of the elements, it is expected to follow unbiunium as the second element of the superactinides and the fourth element of the 8th period. similarly to unbiunium, it is expected to fall within the range of the island of stability.