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We delve into elemental etymology today, and get to investigate a chemical phenomenon.
Featured above: A sheet of anodized niobium. The different colors were made by applying different voltages. Made by Mauro Cateb, Brazilian jeweler and silversmith. CC-BY-SA.
Show Notes
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Episode Script
We’re in a mythological neighborhood on the periodic table. Group 5 leads with Vanadium, and today’s element is named after Niobe, a character from Greek mythology who was the daughter of Tantalus, namesake of the next element in this group. But while Vanadis is a goddess of beauty with a sleigh pulled by cats, Niobe is a much more tragic figure.
She boasted about having fourteen children, comparing herself to the goddess Leto, who only had two children. Well, Leto did not take kindly to this act of hubris. Her two children were Apollo and Artemis, who happened to be expert archers. They put that skill to use, and quicker than you can say “Tisiphone,” Niobe no longer had any children at all.
I’m not sure the punishment fits the crime, there, but those Greek gods really can’t stand for braggadocio. As far as today’s element is concerned, it’s not really so tragic — although, it did lose its original name when a higher authority made a harsh decision.
You’re listening to The Episodic Table Of Elements, and I’m T. R. Appleton. Each episode, we take a look at the fascinating true stories behind one element on the periodic table.
Today, we’re getting to know niobium.
Fabulous names aren’t the only trend in these here parts of the periodic table. Niobium is also the first of the refractory metals, a category of elements that are extremely resistant to heat, abrasion, and chemical attack. That might sound familiar, since we’ve already encountered several elements like that — titanium, chromium, and zirconium, to name a few. And sometimes those elements are considered to be refractory metals, too, but there are five metals that unquestionably meet the defining criteria: Niobium, molybdenum, tantalum, tungsten, and rhenium. These are the metals with the highest melting points, the greatest stability.
This is more of a metallurgical definition than a chemical one, but that makes it no less valid. That’s just how these elements are important to people working in manufacturing industries. One such practical application has been fuel nozzles for rockets. That’s a little unusual — we’re accustomed to seeing lightweight metals like aluminum in aerospace applications, and niobium is over three times more dense than aluminum.1 But if there’s one thing more important than weight considerations, you need to make sure that your rocket won’t disintegrate upon ignition — and niobium is great for that.2
The man who discovered niobium was also in the vehicle industry, but a sort that’s far less grandiose.
John Winthrop, son of John Winthrop, was a man of many talents. He was a physician, alchemist, rock hound, and the first governor of Connecticut. In the course of his rock hounding, he discovered a new mineral specimen, and sent it back to England for other people to study. (This was before the Revolutionary War, naturally.)
But Winthrop is not credited as the discoverer of element 41 — nor should he be. He didn’t perform any special analyses on the mineral. Neither did anyone else, for that matter, for nearly a century. His rock simply sat in the British Museum, drawing little attention to itself. It wasn’t until 1801 that a man named Charles Hatchett took an interest in the little black mineral.
Hatchett was similarly a man of many talents — that was at the time, as now, more of an option if you happened to be a wealthy and powerful man. In his wheelhouse were literal wheels, actually. He helped his father build wagons and coaches for clients who were even wealthier than they were. But he was also an amateur chemist, and that’s why he was drawn to the sample at the museum.
Upon analysis, Hatchett found that this mineral contained a “new earth,” that old-timey term that indicates the discovery of an element. And, as was the practice at the time, he gave this new element a name: “Columbium.”3
Regardless of your feelings on Christopher Columbus, that’s a little different from the other nationalistic names on the periodic table. Hatchett was British, remember, but since the mineral came from America, he thought it would be nice to name it after that place. Of the 25 elements named after places on Earth, maaaybe three others are named for a country other than the discoverer’s home.
The next year, one Andres Ekeberg discovered another new element, one that was very similar to columbium. He called it tantalum. That’s right about when the wheels fell off.4
It can be very difficult to identify transition metals within mineral samples, and over the next couple decades, there was a fair amount of debate surrounding these two elements. Some declared that columbium and tantalum were actually the same element. Others claimed the discovery of other new elements, like ilmenium, dianium, and pelopium.5
Hatchett was still alive during this period, but he basically couldn’t be bothered. He was but a hobbyist, remember, and chemistry wasn’t really his true passion. After his father died, Hatchett took up the family carriage business, and could no longer be bothered with academic squabbles that he had left behind years before.
It’s a shame, really, because all those new hypotheses were incorrect. Columbium and tantalum were distinct from each other, and all those “new” elements were actually just different compounds of those two elements.
Meanwhile, in 1844, Heinrich Rose re-discovered element 41. Noting its similarity to tantalum, he named it niobium, after the daughter of the Phrygian king Tantalus. In 1866, Jean Charles Galissard de Marignac finally sorted everything out — but by then, one of those great global divides was well established. Americans, as you might have guessed, were quite fond of calling the element “columbium.” Europeans, however, rather preferred “niobium.” Neither side was too keen to budge — and for a long time, both names coexisted alongside each other.
This wasn’t the only element with such a problem. Perhaps you remember that beryllium also went by “glucinium” for a time, due to its sweet but deadly taste. Lutetium was also known as “cassiopeium,” and half the world called tungsten “wolfram,” because academics are no more immune to petty disputes than the rest of us.
The situation was getting quite out of hand. Between the 1940s and 50s, an international consortium called the Atomic Weights Commission revoked the right for an element’s discoverer to name that element, much like an exasperated parent might discipline a petulant child. They made executive decisions on the names of more than a dozen different elements: Element 4 was beryllium, for instance. Forty-one was niobium, and 74 was wolfram. Then they washed their hands of the matter: So fed up were those scientists that thereafter, the Atomic Weights Commission would have no part of this whole fiasco. They handed the mess over to the organization that would eventually become the International Union of Pure and Applied Chemistry.6
But what good is a rule that cannot be enforced? Few scientists abandoned their stubbornly held positions just because a committee told them to. Shoddy journalism further complicated the matter, with some newspapers reporting the exact opposite of the decisions the Commission had actually made. A year later, a sort of hostage trade was made: The Americans agreed to call element 41 niobium, if they really must, but 74 would be called tungsten. But in a final concession to the Europeans, tungsten’s chemical symbol would remain W.7
The scientific method is an elegantly impartial method for investigating the universe. Unfortunately, when placed in the imperfect hands of humans, we demonstrate an uncanny ability to make absolutely anything political. I swear, it’s enough to make you cry.
Fittingly for an element with such a fluid identity, it’s also a metal that can wear many faces thanks to the miracle of anodization.
You might own one or two anodized objects. The process is often used to give laptops and phones a colorful sheen, and conveniently makes them a little more durable, too. To accomplish this effect, the metal is dunked in a chemical bath, and zapped with an electrical current. The metal acts as the positive anode in this circuit, hence the name.
This causes the metal to oxidize, forming a layer of niobium oxide evenly across its exposed surfaces. By applying a consistent, finely tuned voltage, it’s possible to control precisely how thick that layer gets.
That’s important, because the thickness of the oxidized layer is the one factor that determines the color that metal becomes. And it does so in a pretty weird way.
Color is a pretty straightforward phenomenon. Light travels as a wave, and the light’s color is determined by its wavelength. If a beam of light has a wavelength of 480 nanometers, it will appear blue. At 700 nanometers, light looks red. And so on. Basically, color is to light what pitch is to sound, with each color being a different note.
The sun projects light that’s traveling at all different wavelengths — like if you smashed every key on a piano. Our eyes perceive that as white light.
When that white light falls upon an object, the object will absorb the light. But it doesn’t absorb every wavelength of light equally. For instance, a strawberry soaks up almost every visible wavelength of light — but not those photons travelling at a rate of 700 nanometers. Those bounce right off the strawberry’s surface. Some of those photons bounce right into our eyes, and we perceive a rich red color.
That’s not what’s going on with anodized surfaces. The oxidized layer of metal doesn’t intrinsically have a color in the same way the strawberry’s surface does. Instead, the electrochemical process creates microscopic ridges that are so small, they interfere with the motion of photons as they strike its surface. It’s kind of similar to how a breakwater causes big ocean waves to disperse into several less intense waves.8
So the white light that strikes the anodized surface gets disturbed, interfering with itself, causing the light that bounces off to take on a particular color. That color is dependent on the angle at which light strikes the surface, and this causes the effect commonly called “iridescence” — sort of an otherworldly shimmer.
Not every metal takes well to anodizing. Imagine iron, for instance: Oxidizing its surface is also known as “covering it in rust.” But it does work well for metals whose oxide forms a strong layer that binds tightly to the raw metal’s surface. Aluminum is the most common of these, but niobium can be anodized to display some gorgeous colors.9
Niobium is also a metal that human bodies tolerate pretty well, so for those two reasons, you should have an easy time adding it to your element collection by visiting a jewelry store. Retailers from Tiffany’s to your local mall’s body piercing shop put element 41 to use, so it’s available at every price point.10
You coin collectors in the audience can get excited, because niobium is frequently used to create colorful commemorative coins. A particularly precious example is a 25-euro coin minted by Austria in 2003. This bimetallic coin was struck in honor of Hall in Tirol, celebrating the 700th anniversary of that town’s establishment. A ring of fine silver surrounds a brilliant blue niobium center.11
Be prepared to empty your wallet if you’d like to collect that specimen. It may have been struck as a 25-euro coin, but you’ll have to shell out close to a thousand bucks to buy it on the collector’s market.
It doesn’t have anything to do with anodization, but that might cause your face to turn red.
Thanks for listening to The Episodic Table of Elements. Music is by Kai Engel. To learn about the world’s bluest fruit, visit episodic table dot com slash N b.
Next time, we’ll try to sort through an even worse identity crisis with molybdenum.
Until then, this is T. R. Appleton, reminding you that your scientific discoveries are worth defending.
Sources
- Angstrom Sciences, Density Of Elements Chart.
- Minor Metals Trade Association, Nb – Niobium (Columbium).
- Philosophical Transactions Of The Royal Society Of London, An Analysis Of A Mineral Substance From North America, Containing A Metal Hitherto Unknown. Charles Hatchett, November 26, 1801.
- Thomas Jefferson National Accelerator Facility – Office Of Science Education, The Element Niobium.
- Elementymology & Elements Multidict, Niobium. Peter van der Krogt.
- Brookhaven National Laboratory, Element 74, The Wolfram Versus Tungsten Controversy. Norman E. Holden, August 11-12, 2008.
- JSTOR Daily, What’s In A Name (Of An Element)? James MacDonald, June 23, 2016.
- Nature, In Your Element: Subtle Niobium. Michael A. Tarselli, January 23, 2015.
- Royal Society Of Chemistry, Chemistry In Its Element: Niobium.
- PeriodicTable.com, Niobium. Theodore Gray.
- Allnumis, 25 Euro 2003.