Niobium, Nb /naɪˈoʊbiəm/ (lat. Niobium; from the name of Niobe – the daughter of Tantalus in ancient Greek mythology * a. niobium; n. Niob, Niobium; f. niobium; i. niobio), is a chemical element of group V of the periodic system of Mendeleev , atomic number 41, atomic mass 92.9064. It has one natural isotope 93Nb, a steel-colored metal.