10 Quick Facts About Cobalt


How well do you know the periodic table? Our series The Elements explores the fundamental building blocks of the observable universe—and their relevance to your life—one by one.

Cobalt hides out in everyday objects and happenings around us, from batteries and blue paint to medical procedures. We've used it for millennia, even before the common era, but it didn't get proper credit until the 18th century. With its 27 protons, cobalt is sandwiched between iron and nickel in the middle portion of the periodic table with the other "transition" metals, which bridge the main group elements located on either side. Here are ten curious facts about this element.


Though you can find cobalt just about everywhere—in the soil, in mineral deposits, and even in crusts on the seafloor—it's always combined with other elements like nickel, copper, iron, or arsenic, such as in the bright crimson arsenate mineral erythrite. It's usually collected as a byproduct of mining for other metals—especially nickel and copper—and, once purified, is a burnished gray color.


Despite being relatively common, it's considered a critical raw material by the European Union because there are few places where it's abundant enough to be mined in larger quantities. The only mine in the world where it's the primary product is in Morocco.


Centuries ago, miners in the mountains of Germany had a great deal of trouble trying to melt down certain ores for useful metals like silver and copper, and even dealt with poisonous fumes released from the rock, which could make them very sick or even kill them. They blamed the kobolds—pesky, underground sprites of local folklore (and more recently, the name of a Dungeons & Dragons species). Though the vapors actually arose from the arsenic also contained in the ores, when chemists later extracted cobalt from these minerals, the name stuck.


It was not until the 1730s that Swedish chemist George Brandt purified and identified cobalt from arsenic-containing ores, then another 50 years until Torbern Bergman, another Swede, verified Brandt's new element. It is worth noting, though, that at the time the elements were simply in an incomplete list and had not been organized into a meaningful table.


People have been using cobalt-containing pigments to get that rich blue hue as far back as the 3rd millennium BCE, when Persians used them to color their necklace beads. From Egypt to China, artisans created blue glass from cobalt compounds for thousands of years. The color was long attributed to the element bismuth, depriving cobalt of pigment fame. 


The famed "cobalt blue" is actually the result of the compound cobalt aluminate. Cobalt in other chemical combinations can also make a variety of other colors. Cobalt phosphate is used to make a violet pigment, and cobalt green is achieved by combining cobalt oxides with zinc oxides.


Cobalt is one of the few elements that are ferromagnetic, which means it can become magnetized when exposed to an external magnetic field. Cobalt remains magnetic at extremely high temperatures, making it very useful for the specialized magnets in generators and hard drives. When mixed with the right metals, cobalt can also help create materials called "superalloys" that keep their strength under huge stress and high temperatures—advantageous, for instance, in a jet engine. Most people, however, can find cobalt hiding closer to home, inside some rechargeable batteries.


Scientists such as chemist Patrick Holland at Yale University are looking at ways to use cobalt in place of the more rare and expensive metals often used in industrial catalysts. These catalysts—chemical "helpers" that speed up reactions—are used in making adhesives, lubricants, or pharmaceutical precursors, for instance. Precious metals like platinum and iridium often make good catalysts, but they are also pricey, can be toxic to humans, and, as precious implies, are not abundant. There is a "big upswing in people looking at iron, nickel, and cobalt because of their price," Holland tells Mental Floss.

All three could be viable options in the future. The challenge, Holland says, is "walking the tightrope" between creating an effective, reactive catalyst and one that is too reactive or overly sensitive to impurities.


The metal perches in the middle of the impressively complex molecule vitamin B12—a.k.a. cobalamin—which is involved in making red blood cells and DNA, and helps keep your nervous system healthy. Cobalt also lends an extra distinction to B12: It's the only vitamin that contains a metal atom.

To measure B12 intake in patients, doctors use a "labeled" version of B12 in which the cobalt atom is replaced with a radioactive cobalt isotope. Oncologists and technicians also use the radiation from cobalt isotopes in some cancer therapies as well as to sterilize medical and surgical tools. These days, cobalt alloys are even found in artificial hip joints and knees.


In the 1960s, some breweries added cobalt chloride to their beers because it helped maintain the appealing foam that builds when beer is poured. By 1967, more than 100 heavy beer drinkers in Quebec City, Minneapolis, Omaha, and Belgium had suffered heart failure, and nearly half of them died. At the time, doctors were also administering cobalt to patients for medical reasons without causing this severe effect, so the blame couldn't lie with the metal alone. After studying the remains of the deceased, scientists proposed that the so-called "cobalt-beer cardiomyopathy" had been caused by an unhealthy mélange of cobalt, high alcohol intake, and poor diet. The FDA banned the use of cobalt chloride as a food additive shortly after. 

10 Facts About the Element Lead


Lead (Pb) is one of the most infamous elements in the periodic table. Though it’s now widely known as the source of lead poisoning, humans have been using the heavy metal for thousands of years. It’s soft, has a relatively low melting point, is easy to shape, and doesn’t corrode much, making it incredibly useful. It’s also relatively abundant and easy to extract. But lead is so much more than just No. 82 on the periodic table. Here are 10 facts about the element lead.

1. The element lead is easy to extract.

One reason people have been using lead for so long is because it’s so easy to extract from galena, or lead sulfide. Thanks to lead’s low melting point of 621.4°F (compare that to the melting point of iron, 2800°F), all you have to do to smelt it is put the rocks in a fire, then extract the lead from the ashes once the fire burns out.

Galena is still one of the major modern sources of lead. Missouri, the biggest producer of lead in the U.S. (and home to the largest lead deposits in the world), designated galena as its official state mineral in 1967. Galena is also the state mineral of Wisconsin, where it has been mined since at least the 17th century. Several towns across the U.S. are named after the mineral as well, most notably Galena, Illinois, one of the centers of the American “Lead Rush” of the 19th century.

2. People have been using lead since prehistory.

The oldest smelted lead object ever found was discovered in a cave in Israel in 2012. Researchers have dated the wand-shaped tool—potentially a spindle whorl—to the late 4000s BCE, tracing its origins to lead ores in the Taurus mountains of what is now Turkey.

3. Lead poisoning can be fatal.

Lead has a fairly similar chemical structure to calcium. Both have two positively charged ions. Because of that, inside the body, the toxic metal can bind to the same proteins as the vital mineral. Over time, lead poisoning occurs as the element crowds out the minerals your body needs to function, including not just calcium, but iron, zinc, and other nutrients.

Lead can travel through the body in the same way that those minerals can, including passing through the brain-blood barrier and into the bones. As a result, exposure to lead—whether through paint, pipes, contaminated soil, or any other means—can be very dangerous, especially for children, for whom lead poisoning can cause learning disabilities, delayed growth, brain damage, coma, and death. Scientists believe there is no safe threshold for lead exposure.

4. Ancient Romans really loved lead.

Lead use reached new heights during the Roman Empire. Ancient Romans used lead to make cookware, water pipes, wine jugs, coins, and so much more. Lead acetate was even used as a sweetener, most often in wine. As a result of ingesting a little lead with every bite of food and sip of water or wine, modern researchers have argued that two-thirds of Roman emperors (as well as plenty of common folk) exhibited symptoms of lead poisoning. A 20th-century examination of the body of Pope Clement II, who died in 1047, showed that lead poisoning led to the religious leader’s sudden demise, too—though there’s still some speculation of whether he was poisoned by an enemy or if he simply drank too much lead-sweetened wine.

5. Lead is a very stable element.

Lead atoms are “doubly magic.” In physics, the numbers 2, 8, 20, 28, 50, 82, and 126 are considered “magic” because those numbers of protons or neutrons completely fill up the atomic nucleus. Lead has 126 neutrons and 82 protons—two magic numbers. As a result, lead isotopes are incredibly stable. Lead-208 is the heaviest stable atom.

6. Lead made car engines quieter—at a high cost.

It’s not surprising that we no longer add lead to gasoline (TIME magazine called it one of the world’s worst inventions back in 2010). But why was it ever there in the first place?

In 1921, a General Motors researcher discovered that adding tetraethyl lead to gasoline reduced “engine knock” in cars, when pockets of air and fuel explode in the wrong place and time in a combustion engine. In addition to producing a loud sound, it also damages the engine. While there were other available chemicals like ethanol and tellurium that could similarly provide the octane boost to reduce knocking, leaded gasoline was easier and cheaper to produce, and unlike tellurium, it didn't reek of garlic.

Unfortunately, it came at a high cost for the refinery workers that produced leaded gasoline (who many of whom were sickened, driven mad, and killed by their exposure to it) and the environment as a whole.

In the 1960s, geochemist Clair Patterson was trying to measure the exact age of the Earth when he discovered a shocking amount of lead contamination in his lab—and everything he tested, from his tap water to dust in the air to his skin and samples of his dandruff. As he continued to experiment, he discovered that lead levels in ocean water began to rise drastically around the same time that lead became a common gasoline additive. Every car on the road was belching lead straight into the atmosphere.

Patterson would later become the driving force in forcing the U.S. government to ban leaded gasoline. (You can read more about him in our feature, “The Most Important Scientist You’ve Never Heard Of.”)

7. Lead was used in paintings …

Historically, lead wasn’t just prized for being an easy-to-shape metal; it was also valued for its color. Though most of us know that lead was historically used in house paint (and still continues to hide in the walls of some homes today), it was also a popular ingredient in fine art for thousands of years.

Produced since antiquity, lead white (also known as Cremnitz white) was a favorite paint pigment of the Old Masters of the 17th and 18th centuries, including artists like Johannes Vermeer and Rembrandt van Rijn.

“For two millennia, white leads—basic lead carbonate and sulfate—were the only white pigments that could deliver moderately durable whiteness and brightness into a drab world of grays and earth colors," pigment experts Juergen H. Braun and John G. Dickinson wrote in the third edition of Applied Polymer Science: 21st Century in 2000. Like a number of other pigments prior to the advent of synthetic paints, its toxicity was general knowledge, but for many painters, the risk was worth it to achieve the color they wanted. You can still buy it today, but it has largely been replaced with the safer titanium white.

Lead white isn't the only lead paint lurking in many famous paintings from history. Dutch artists like Vermeer also favored lead tin yellow, which you can see in his masterpiece The Milkmaid.

8. … and in makeup.

During the 18th century, both men and women used white lead powder to achieve fashionably ghostly complexions, though it was known to be toxic. They powdered their hair with white lead powder, too. The dangerous trend caused eye inflammation, tooth rot, baldness, and eventually, death. To top it off, using lead powder made the skin blacken over time, so wearers needed to apply more and more of the powder to achieve their intended look. Queen Elizabeth I, who lost most of her teeth and much of her hair by the end of her life, reportedly was wearing a full inch of lead makeup on her face when she died. While her cause of death remains unclear, one popular theory holds that she was killed by blood poisoning from her longtime reliance on those lead-filled cosmetics.

Researchers have hypothesized that several other famous historical figures either suffered from or died from lead poisoning, including painters like Vincent van Gogh and Francisco Goya. In several cases, exhumations have proved this: A 2010 analysis of what are thought to be Caravaggio’s bones showed very high levels of lead (enough to drive him crazy, if not outright kill him) likely from his exposure to lead paint throughout his life. Hair and skull fragments believed to belong to Ludwig van Beethoven also show very high lead levels, potentially from the wine he drank.

9. Lead is a superconductor.

Which means that if it is cooled below a certain temperature, it loses all electric resistance. If you were to run a current through lead wire that has a temperature below 7.2K (-446.71°F), it would conduct that current perfectly without losing any energy to heat. A current running through a lead ring could continue flowing forever without an outside energy source.

Like other superconductors, lead is diamagnetic—it is repelled by magnetic fields.

10. On Venus, it snows lead.

Venus is the hottest planet in the solar system, with an average surface temperature of 867°F. That’s far above lead’s 621.4°F melting point. In 1995, scientists discovered what appeared to be metallic “snow” on the mountains of Venus—a planet too hot to have water ice. In 2004, researchers at Washington University in St. Louis discovered that Venusian “snow” was probably a mixture of lead sulfide and bismuth sulfide.

This “snow” forms because Venus’s high temperatures vaporize minerals on the planet’s surface, creating a kind of metallic mist that, when it reaches relatively cooler altitudes, condenses into metallic frost that falls on the planet’s tallest peaks.

How Cold Is It in Canada? Niagara Falls Has Frozen Over

Aaron Vincent Elkaim, Getty Images
Aaron Vincent Elkaim, Getty Images

The cold snap that's gripped the northeast in an icy, subzero chill has made it hard to roll down frozen car windows and navigate roads. Elsewhere, it's having a significantly more spectacular effect: The roaring cascade of water at Niagara Falls at the United States/Canada border has slowed and even come to a stop in some areas, having effectively frozen over.

CNN reports that extreme temperatures have arrested the famous waterfall in spots, creating a kind of winter wonderland that some observers have compared to the handiwork of Elsa in Disney's Frozen. Here's what a similar scene looked like in 2015:

Visitors observe frozen areas of Niagara Falls in 2015
Aaron Vincent Elkaim, Getty Images

And here's a look at footage captured in 2019:

While covered by a sheet of ice, the Falls are not frozen solid: The volume and force of water prevents that. In the 1960s, steel ice booms were added to prevent large blocks from forming farther up the river that could slow the water enough to cause freezing. Instead, it's the surface water and mist that ices over, creating an aesthetically intriguing appearance. If it gets cold enough, ice can form as the water falls, leading to a large deposit on the bottom that can grow to over 40 feet thick.

It's rare for the Falls to come to a complete halt, but before the advent of the ice booms, it was a possibility. On March 30, 1848, gale force winds pushed ice floes from Lake Erie to the mouth of the Niagara River, creating a natural dam and effectively turning off the rushing water. People began walking over the dry riverbed and collected resurfaced weapons from the War of 1812; others thought it was a sign of the end of the world. Niagara Falls has never experienced a near-total interruption since.

[h/t CNN]