Ununtrium is a chemical element with atomic number 113. It has a temporary name and temporary symbol Uut. It is an extremely radioactive synthetic element (an element that can be created in a laboratory but is not found in nature); its most stable known isotope, ununtrium-286, has a half-life of 20 seconds. It is also known as eka-thallium or simply element 113. Ununtrium was first created in 2003 by the Joint Institute for Nuclear Research in Dubna, Russia, although this discovery is still awaiting confirmation by IUPAC.