mode after is beta emission with some neutron emission occurring in the first mode of the two mode decay of Nb-104, 109 and 110.Nb-95 (35 days ) and Nb-97 (72 minutes) and heavier isotopes (halflives in seconds) are fission products in significant quantity, as the other isotopes are shadowed by stable or very long-lived (Zr-93) isotopes of the preceding element zirconium from production via beta decay of neutron-rich fission fragments. Nb-95 is the decay product of Zr-95 (64 days), so disappearance of Nb-95 in used nuclear fuel is slower than would be expected from its own 35 day halflife alone. Tiny amounts of the other isotopes may be produced as direct fission products.atomic mass: 92.90638 (2) u. br/>
is in many ways similar to its predecessors in group 5. It reacts with most nonmetals at high temperatures: niobium reacts with fluorine at room temperature, with chlorine and hydrogen at 200 В° C, and with nitrogen at 400 В° C, giving products that are frequently interstitial and nonstoichiometric. The metal begins to oxidize in air at 200 В° C, and is resistant to corrosion by fused alkalis and by acids, including aqua regia, chlorhydric, sulfuric, nitric and phosphoric acids. Niobium is attacked by hot, concentrated mineral acids, such as fluorhydric acid and fluorhydric/nitric acid mixtures. Although niobium exhibits all the formal oxidation states from +5 down to -1, its most stable state is +5. p> Niobium is able to form oxides with the oxidation states +5 (Nb2O5), +4 (NbO2) and +3 (Nb2O3), as well as with the rarer oxidation state +2 (NbO). The most stable oxidation state is +5, the pentoxide which, along with the dark green non-stoichiometric dioxide, is the most common of the oxides. Niobium pentoxide is used mainly in the production of capacitors, optical glass, and as starting material for several niobium compounds. The compounds are created by dissolving the pentoxide in basic hydroxide solutions or by melting it in another metal oxide. Examples are lithium niobate (LiNbO3) and lanthanum niobate (LnNbO4). In the lithium niobate, the niobate ion NbO3? is not alone but part of a perovskite-like structure, while the lanthanum niobate contains lone ions. Lithium niobate, which is a ferroelectric, is used extensively in mobile telephones and optical modulators, and for the manufacture of surface acoustic wave devices. It belongs to the ABO3 structure ferroelectrics like lithium tantalate and barium titanate.forms halogen compounds in the oxidation states of +5, +4, and +3 of the type NbX5, NbX4, and NbX3, although multi-core complexes and substoichiometric compounds are also formed. Niobium pentafluoride (NbF5) is a white solid with a melting point of 79.0 В° C and niobium pentachloride (NbCl5) is a yellowish-white solid (see image at left) with a melting point of 203.4 В° C. Both are hydrolyzed by water and react with additional niobium at elevated temperatures by forming the black and highly hygros...
