Nihonium is a chemical element with atomic number 113. It has a temporary name and temporary symbol Nh. 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, nihonium-286, has a half-life of 20 seconds. It is also known as eka-thallium or simply element 113. Nihonium was first created in 2003 by the Joint Institute for Nuclear Research in Dubna, Russia, although this discovery is still awaiting confirmation by IUPAC, on Jan, 4, 2016 Nihonium has been confirmed that it has been discovered along with Oganesson, and Tennessine.
It's old name was Ununtrium.
In the periodic table, it is a p-block transactinide element. It is a member of the 7th period and is placed in the boron group, although it has not been confirmed to behave as the heavier homologue to thallium in the boron group. Nihonium is calculated to have some similar properties to its lighter homologues, boron, aluminium, gallium, indium, and thallium, although it should also show several major differences from them. Unlike all the other p-block elements, it is predicted to show some transition metal character. 8th June,2016,The IUPAC decided to change Ununtrium to Nihonium(Nh).