The name reflects the great similarity between the two elements in their physical and chemical properties, which makes them difficult to distinguish.

German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element, which he named niobium.

In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably.

Although these alloys contain a maximum of 0.1%, the small percentage of niobium enhances the strength of the steel by scavenging carbide and nitride.

[10][11][12] He found a new element in a mineral sample that had been sent to England from Connecticut, United States in 1734 by John Winthrop FRS (grandson of John Winthrop the Younger) and named the mineral "columbite"" and the new element "columbium" after Columbia, the poetic name for the United States.

[16] This conclusion was disputed in 1846 by German chemist Heinrich Rose, who argued that there were two different elements in the tantalite sample, and named them after children of Tantalus: niobium (from Niobe) and pelopium (from Pelops).

[20] The differences between tantalum and niobium were unequivocally demonstrated in 1864 by Christian Wilhelm Blomstrand[20] and Henri Étienne Sainte-Claire Deville, as well as Louis J. Troost, who determined the formulas of some of the compounds in 1865[20][21] and finally by Swiss chemist Jean Charles Galissard de Marignac[22] in 1866, who all proved that there were only two elements.

[21] In 1961, the American physicist Eugene Kunzler and coworkers at Bell Labs discovered that niobium–tin continues to exhibit superconductivity in the presence of strong electric currents and magnetic fields,[25] making it the first material to support the high currents and fields necessary for useful high-power magnets and electrical power machinery.

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, as a result of the lanthanide contraction.

[21] Although its corrosion resistance is not as outstanding as that of tantalum, the lower price and greater availability make niobium attractive for less demanding applications, such as vat linings in chemical plants.

92Nb, along with 94Nb, has been detected in refined samples of terrestrial niobium and may originate from bombardment by cosmic ray muons in Earth's crust.

[56] The three largest currently mined deposits of pyrochlore, two in Brazil and one in Canada, were found in the 1950s, and are still the major producers of niobium mineral concentrates.

[21] The largest deposit is hosted within a carbonatite intrusion in Araxá, state of Minas Gerais, Brazil, owned by CBMM (Companhia Brasileira de Metalurgia e Mineração); the other active Brazilian deposit is located near Catalão, state of Goiás, and owned by China Molybdenum, also hosted within a carbonatite intrusion.

[58][59] The third largest producer of niobium is the carbonatite-hosted Niobec mine, in Saint-Honoré, near Chicoutimi, Quebec, Canada, owned by Magris Resources.

It is also readily prone to hydrolysis and is barely soluble in dilute solutions of hydrochloric, sulfuric, nitric and phosphoric acids due to the precipitation of hydrous Nb oxide.

[86] The main niobium carbide is NbC, an extremely hard, refractory, ceramic material, commercially used in cutting tool bits.

[90][91] Quantities of niobium are used in nickel-, cobalt-, and iron-based superalloys in proportions as great as 6.5%[88] for such applications as jet engine components, gas turbines, rocket subassemblies, turbo charger systems, heat resisting, and combustion equipment.

[92] One example superalloy is Inconel 718, consisting of roughly 50% nickel, 18.6% chromium, 18.5% iron, 5% niobium, 3.1% molybdenum, 0.9% titanium, and 0.4% aluminium.

It is composed of 89% niobium, 10% hafnium and 1% titanium and is used for liquid-rocket thruster nozzles, such as the descent engine of the Apollo Lunar Modules.

[95] The reactivity of niobium with oxygen requires it to be worked in a vacuum or inert atmosphere, which significantly increases the cost and difficulty of production.

Vacuum arc remelting (VAR) and electron beam melting (EBM), novel processes at the time, enabled the development of niobium and other reactive metals.

The project that yielded C-103 began in 1959 with as many as 256 experimental niobium alloys in the "C-series" (C arising possibly from columbium) that could be melted as buttons and rolled into sheet.

Wah Chang Corporation had an inventory of hafnium, refined from nuclear-grade zirconium alloys, that it wanted to put to commercial use.

Competing niobium alloys from that era included FS85 (Nb-10W-28Ta-1Zr) from Fansteel Metallurgical Corp., Cb129Y (Nb-10W-10Hf-0.2Y) from Wah Chang and Boeing, Cb752 (Nb-10W-2.5Zr) from Union Carbide, and Nb1Zr from Superior Tube Co.[95] The nozzle of the Merlin Vacuum series of engines developed by SpaceX for the upper stage of its Falcon 9 rocket is made from a niobium alloy[clarification needed].

[26] The superconducting radio frequency (SRF) cavities used in the free-electron lasers FLASH (result of the cancelled TESLA linear accelerator project) and XFEL are made from pure niobium.

[104] The high sensitivity of superconducting niobium nitride bolometers make them an ideal detector for electromagnetic radiation in the THz frequency band.

[105] Lithium niobate, which is a ferroelectric, is used extensively in mobile telephones and optical modulators, and for the manufacture of surface acoustic wave devices.

[119][120][121] Niobium is used in arc welding rods for some stabilized grades of stainless steel[122] and in anodes for cathodic protection systems on some water tanks, which are then usually plated with platinum.

[126] Niobium is employed in the atomic energy industry for its high temperature and corrosion resistance, as well as its stability under radiation.

Rats treated with a single injection of niobium pentachloride or niobates show a median lethal dose (LD50) between 10 and 100 mg/kg.