Why Is Niobium Important in Chemistry?
Formerly known as Columbium, Niobium is a beautiful, white metal that changes to varying shades of blue, yellow and green when exposed to the air and the elements. Niobium was the subject of much discourse and scientific inquiry, when Charles Hatchett, a British scientist, first stumbled upon it in the British Museum, in 1801. Coming across a sample of metal labelled Columbite, Charles heated it with potassium, and on adding an acid, obtained the precipitate of what is now known as Niobium.
Further, in 1844, the German scientist-chemist Heinrich Rose discovered that columbite contained traces of both Tantalum and Niobium. This eventually led to more research on the uses of Niobium and its properties.
More about Niobium
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The element Niobium has a fascinating history. In 1734, John Winthrop discovered a mysterious ore in Massachusetts, which he promptly sent to England. For several years, the ore would sit in the British Museum, unnoticed, till Charles Hatchett eventually came across it in 1801, and named it Columbium, after Columbia.
Consequently, in 1844, when Heinrich Rose discovered traces of Tantalum and another element in columbite, he was convinced that this new element was Niobium. Two decades down the line, a Swiss scientist called Jean Charles Galissard isolated the metallic Niobium by heating its chloride.
International Union of Pure and Applied Chemistry renamed it as Niobium in 1949, although several metallurgists continue to call it Columbium.
Before we get started with the diverse uses of Niobium, let us take a look at a few essential facts about this rare metal.
Chemical Properties of Niobium
Niobium takes on a blue to greenish shade when exposed to air and its elements, at room temperature.
It has a relatively high melting point, and in its elemental form, its melting point can go up to 2,468 °C.
Further, Niobium has a density that is lower than most other refractory metals.
Also, it is anti-corrosive and has high superconductivity properties.
Niobium usually forms layers of dielectric oxides when exposed to air.
It is almost identical in terms of size, to tantalum atoms and exhibits Lanthanide contractions.
It is less electropositive than Zirconium.
Thanks to the Lanthanide contractions and similar size, it has chemical properties that quite resemble that of Tantalum.
The Following Table throws Light on Some more Properties and Facts about Niobium.
Activity: Before learning all about the physical properties of Niobium, ask your teacher or lookup Google for the various uses of Niobium. Find out how useful it is, and if industries actively use the metal in their equipment.
Pop Quiz 1
1. What is the Atomic Weight of Niobium?
41
40
92.906
None of the above.
Physical Properties of Niobium
Niobium is a greyish, ductile and lustrous metal that is found in Group 5 of the periodic table.
It has paramagnetic properties.
Niobium has an electronic configuration of [Kr]4d45s1, with electrons in the outermost shells. This is not typical for elements in Group 5.
It has a body-centred cubic crystal form, that is present at both absolute zero to melting point temperatures.
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At temperatures conducive to cryogenesis, Niobium changes into a superconductor.
It also boasts of the largest magnetic penetration depth, known to elements.
Along with Technetium and Vanadium, Niobium comprises the three elemental Type II superconductors.
Depending on how pure a sample of Niobium is, the superconductivity varies from moderate to high.
In its purest form, Niobium is soft, ductile but can turn hard if it contains impurities.
Pop Quiz 2
1. What is Niobium Density?
8.69 g cm-3
8.57 g cm-3
8 g cm-3
None of the above.
2. What is the Atomic Number of Niobium?
36
40
41
50
Did You Know?
Niobium was named after Niobe, the Greek Goddess of tears, who incidentally, happens to be King Tantalus’s daughter. Yes, the very same Tantalus, who Tantalum was named after. What is more, Niobium and Tantalum are always found existing together in nature, according to a report by the U.S. Geological Survey.
Keeping these few points in mind, let us look ahead and learn all about the uses of Niobium.
Uses of Niobium
Niobium is often used in the production of alloys and specially manufactured stainless steel containers, equipment or vessels, that exhibit resistance to very high temperatures.
Even trace amounts of Niobium impart tremendous mechanical strength to other metals, thus finding application in a number of metal industries.
Niobium carbide is also employed in cutting tools.
Stainless steel alloys, such as the ones for jets, missiles, nuclear reactors, cutting tools, super-powerful magnets, welding rods and pipelines are also made of Niobium.
Alloys made of Niobium-tin or Niobium-Titanium are mostly used in wires and superconducting magnets. These magnets have the capacity to produce powerful magnetic fields.
In its purest form, Niobium is employed in the manufacture of superconducting accelerators and particle accelerators.
Surgical implants nowadays, make increasing use of Niobium, as it does not react to organic, especially, human tissues.
In the past, this metal was mined mainly as a constituent of columbite. Some prominent Niobium mining areas in the world include Canada, Russia, Zaire and Nigeria.
Around 25,000 tonnes of Niobium are mined and produced every year, and this is only a fraction of the total amount of niobium reserves in the world.
Significantly, Niobium is also used to manufacture NMR equipment, prosthetics, pacemakers and MRI scanners. It finds prominent use in the medicine and implants industry.
Thanks to its versatility and beneficial microalloying properties, it is used in small amounts in the structures of modern automobiles and vehicles as well. In addition to this, Niobium is used in iron and cobalt-based alloys. These alloys are widely used in the components of jet engines, turbocharger systems, has turbines, heat-resisting equipment and rocket super assemblies.
Interestingly, such superalloys have been extensively used in space programs and airframe systems. For instance, the Gemini program and the Apollo Service Module. More recently, the Merlin Vacuum series, a flagship range of engines developed by the hugely-popular SpaceX, has made use of a Niobium alloy for its Falcon 9 rocket.
Some Other Unique Applications of Niobium Include:
Lithium niobate, a ferroelectric compound, is widely used in cellular phones and surface acoustic wave equipment.
Owing to their hypoallergenic nature, some alloys of Niobium are used in prosthetics and beautiful colours for costume jewellery.
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Isotopes of Niobium
In its natural state, as found in the Earth's crust, Niobium consists of the stable isotope 93Nb. Almost over 32 radioisotopes have been synthesised till date, of which 92Nb is the most stable and its half-life is 34.7 million years. The least stable isotope of Niobium is 113Nb.
Only around 25 isomers of Niobium have been discovered as yet, and their atomic masses range from 84 to 104. It is the 34th most commonly occurring element in the Earth's crust and is not found freely existing in nature but in combination with other elements.
This was all about the rare metal Niobium and its diverse properties. For more on the Group 5 elements of the Periodic Table, refer to our broad range of free PDF study material, reference notes and sample papers. Download the Vedantu app and watch live demo videos on your favourite chemistry topics for enhanced learning.
FAQs on Niobium: Key Properties, Uses, and Isotopes
1. What is Niobium and where is it located on the periodic table?
Niobium (Nb) is a chemical element with atomic number 41. It is a lustrous, grey, ductile metal located in Group 5 and Period 5 of the periodic table, placing it among the transition metals. Due to its properties, it is often found geologically with the element tantalum.
2. What are the most important uses of Niobium in modern industry?
Niobium's primary use is as an alloying agent. Its most significant applications include:
- Manufacturing high-strength, low-alloy (HSLA) steels used in pipelines, car bodies, and structural components.
- Creating superalloys for high-temperature environments like jet engines, gas turbines, and rocket subassemblies.
- Producing superconducting magnets for MRI scanners and particle accelerators.
- Use in specialty stainless steel for chemical plants and nuclear reactors due to its corrosion resistance.
3. What are the key physical and chemical properties of Niobium?
Niobium exhibits several key properties. Physically, it is a ductile and lustrous grey metal with a high melting point of 2,477 °C and a density of 8.57 g/cm³. Its atomic mass is approximately 92.906 u. Chemically, it is highly resistant to corrosion due to the formation of a passive oxide layer. It is also paramagnetic and becomes a superconductor at very low temperatures.
4. How does Niobium's electronic configuration explain its chemical behavior?
Niobium's electronic configuration is [Kr] 4d⁴ 5s¹. This configuration is an exception to the Aufbau principle, as one electron moves from the 5s to the 4d orbital to achieve a more stable state. This arrangement allows Niobium to exhibit multiple oxidation states, with +5 being the most common and stable. The availability of d-electrons is also responsible for its ability to form complex ions and coloured compounds, characteristic of transition metals.
5. Why is Niobium often compared to Tantalum?
Niobium (Nb) and Tantalum (Ta) are often compared because they are considered chemical twins. They share the same group (Group 5) and have nearly identical atomic radii due to the lanthanide contraction. This similarity in size and electronic structure results in very similar chemical properties, making them difficult to separate from each other in their ores, where they commonly occur together.
6. What is microalloying, and why is Niobium crucial for this process in steel production?
Microalloying is the process of adding very small quantities (typically less than 0.1%) of an element to steel to significantly improve its mechanical properties. Niobium is crucial for this because it forms extremely fine precipitates of niobium carbide (NbC) and niobium nitride (NbN) within the steel matrix. These tiny particles pin the grain boundaries during processing, resulting in a much finer grain structure, which dramatically increases the steel's strength, toughness, and weldability.
7. Why is Niobium considered a critical and strategic metal?
Niobium is considered a critical metal because of its indispensable role in high-performance applications and its concentrated supply chain. It is essential for the aerospace, defense, and energy sectors in creating superalloys and high-strength steels for which there are few effective substitutes. Since a vast majority of the world's supply is mined in specific regions, its availability is geographically constrained, making it strategically important for industrial nations.
8. In what forms is Niobium found in nature?
Niobium does not exist as a free element in nature. It is primarily found in minerals, most commonly in pyrochlore, which is the main commercial source. It is also found in other minerals like columbite (often called niobite-tantalite) and euxenite. In these minerals, Niobium is almost always found alongside Tantalum due to their similar chemical properties.
