Biography & contributions
Charles Hatchett was an English chemist born on January 02, 1765 – died on March 10, 1847. Hatchett was well known for his discovery of niobium periodic table element.
Niobium
Niobium is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. Niobium becomes a superconductor at cryogenic temperatures. Niobium is slightly less electropositive and more compact than its predecessor in the periodic table, zirconium, whereas it is virtually identical in size to the heavier tantalum atoms, owing to the lanthanide contraction. Niobium, more plentiful than lead and less abundant than copper in the Earth’s crust, occurs dispersed except for relatively few minerals.
Niobium is estimated to be the 33rd most common element in the Earth’s crust, with 20 ppm. Niobium is in many ways similar to tantalum and zirconium. Niobium can be extracted from the ores by first fusing the ore with alkali, and then extracting the resultant mixture into hydrofluoric acid, HF. Current methodology involves the separation of tantalum from these acid solutions using a liquid-liquid extraction technique.
It reacts with most nonmetals at high temperatures: niobium reacts with fluorine at room temperature, with chlorine and hydrogen at 200 °C, and with nitrogen at 400 °C, giving products that are frequently interstitial and nonstoichiometric. Niobium forms halides in the oxidation states of +5 and +4 as well as diverse substoichiometric compounds. Niobium is an effective microalloying element for steel. Adding niobium to the steel causes the formation of niobium carbide and niobium nitride within the structure of the steel.
Niobium and some niobium alloys are physiologically inert and thus hypoallergenic therefore it is used in pacemakers. Niobium treated with sodium hydroxide forms a porous layer that aids osseointegration. Niobium is used as a precious metal in commemorative coins, often with silver or gold. Other applications of niobium include its use in welding, nuclear industries, electronics, optics, numismatics and jewelry. It is resistant to corrosion by fused alkalis and by acids, including aqua regia, hydrochloric, sulfuric, nitric and phosphoric acids. Niobium is attacked by hydrofluoric acid and hydrofluoric/nitric acid mixtures.
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