ion, the name niobium was chosen for element 41 at the 15th Conference of the Union of Chemistry in Amsterdam in 1949. A year later this name was officially adopted by the International Union of Pure and Applied Chemistry (IUPAC) after 100 years of controversy, despite the chronological precedence of the name Columbium. The latter name is still sometimes used in US industry. This was a compromise of sorts; the IUPAC accepted tungsten instead of wolfram, in deference to North American usage; and niobium instead of columbium, in deference to European usage. Not everyone agreed, and while many leading chemical societies and government organizations refer to it by the official IUPAC name, many leading metallurgists, metal societies, and the United States Geological Survey still refer to the metal by the original "columbium".
is a lustrous, grey, ductile, paramagnetic metal in group 5 of the periodic table (see table to right), although it has an atypical configuration in its outermost electron shells compared to the rest of the members . (This can be observed in the neighborhood of niobium (41), ruthenium (44), rhodium (45), and palladium (46).) br/>
metal takes on a bluish tinge when exposed to air at room temperature for extended periods. Despite presenting a high melting point in elemental form (2,468 В° C), it has a low density in comparison to other refractory metals. Furthermore, it is corrosion resistant, exhibits superconductivity properties, and forms dielectric oxide layers. These properties-especially the superconductivity-are strongly dependent on the purity of the niobium metal. When very pure, it is comparatively soft and ductile, but impurities make it harder.is slightly less electropositive and smaller than its predecessor in the periodic table, zirconium, while it is virtually identical in size to the heavier tantalum as a consequence of the lanthanide contraction. As a result, niobium's chemical properties are very similar to the chemical properties of tantalum, which appears directly below niobium in the periodic table. Although its corrosion resistance is not as outstanding as that of tantalum, its lower price and greater availability make niobium attractive for less exact uses such as linings in chemical plants. p align="justify"> of niobium
occurring niobium (Nb) is composed of one stable isotope (Nb-93). The most stable radioisotopes are Nb-92 with a half-life of 34.7 million years, Nb-94 (half life: 20300 years), and Nb-91 with a half life of 680 years. There is also a meta state at 31 keV whose half-life is 16.13 years. Twenty three other radioisotopes have been characterized. Most of these have half lives that are less than two hours except Nb-95 (35 days), Nb-96 (23.4 hours) and Nb-90 (14.6 hours). The primary decay mode before the stable Nb-93 is electron capture and the primary ...
