How many scientists does it take to discover five elements? More than you might think…

My last post chronicled (see what I did there?) a meandering stroll through all 118 elements in the periodic table. As I read through all the pieces of that thread, I kept wanting to find out more about some of the stories. This is the international year of the periodic table, after all — what better time to go exploring?

But, here’s the thing: 118 is a lot. It took ages even just to collect all the (mostly less than) 280-character tweets together. Elemental stories span the whole of human existence and are endlessly fascinating, but telling all of them in any kind of detail would take whole book (not a small one, either) and would be a project years in the making. So, how about instead having a look at some notable landmarks? A sort of time-lapse version of elemental history and discovery, if you will…


The word “carbon” comes from the Latin “carbo”, meaning coal and charcoal.

Let’s begin the story with carbon: fourth most abundant element in the universe and tenth most abundant in the Earth’s crust (give or take). When the Earth first formed, about 4.54 billion years ago, volcanic activity resulted in an atmosphere that was mostly carbon dioxide. The very earliest forms of life evolved to use carbon dioxide through photosynthesis. Carbon-based compounds make up the bulk of all life on this planet today, and carbon is the second most abundant element in the human body (after oxygen).

When we talk about discovering elements, our minds often leap to “who”. But, as we’ll see throughout this journey, that’s never an entirely straightforward question. The word “carbon” comes from the Latin carbo, meaning coal and charcoal. Humans have known about charcoal for many thousands of years — after all, if you can make a fire, it’s not long before you start to wonder if you can do something with this leftover black stuff. We’ll never know who first “discovered” carbon. But we can be sure of one thing: it definitely wasn’t an 18th century European scientist.

Diamond is a form of carbon used by humans for over 6000 years.

Then there are diamonds, although of course it took people a bit longer to understand how diamonds and other forms of carbon were connected. Human use of diamonds may go back further than we imagine, too. There’s evidence that the Chinese used diamonds to grind and polish ceremonia tools as long as 6,000 years ago.

Even the question of who first identified carbon as an element isn’t entirely straightforward. In 1722, René Antoine Ferchault de Réaumur demonstrated that iron was turned into steel by absorbing some substance. In 1772, Lavoisier showed for the first time that diamonds could burn (contrary to a key plot point in a 1998 episode of Columbo).

In 1779, Scheele demonstrated that graphite wasn’t lead, but rather was a form of charcoal that formed aerial acid (today known as carbonic acid) when it was burned and the products dissolved in water. In 1786 Claude Louis Berthollet, Gaspard Monge and C. A. Vandermonde again confirmed that graphite was mostly carbon, and in 1796, Smithson Tennant showed that burning diamond turned limewater milky — the established test for carbon dioxide gas — and argued that diamond and charcoal were  chemically identical.

Even that isn’t quite the end of the story: fullerenes were discovered 1985, and Harry Kroto, Robert Curl, and Richard Smalley were awarded a Nobel Prize for: “The discovery of carbon atoms bound in the form of a ball” in 1996.

Type “who discovered carbon” into a search engine and Lavoisier generally appears, but really? He was just one of many, most of whose names we’ll never know.


Brass, an alloy of zinc, has been used for thousands of years.

Now for the other end of the alphabet: zinc. It’s another old one, although not quite as old as carbon. Zinc’s history is inextricably linked with copper, because zinc ores have been used to make brass alloys for thousands of years. Bowls made of alloyed tin, copper and zinc have been discovered which date back to at least 9th Century BCE, and many ornaments have been discovered which are around 2,500 years old.

It’s also been used in medicine for a very long time. Zinc carbonate pills, thought to have been used to treat eye conditions, have been found on a cargo ship wrecked off the Italian coast around 140 BCE, and zinc is mentioned in Indian and Greek medical texts as early as the 1st century CE. Alchemists burned zinc in air in 13th century India and collected the white, woolly tufts that formed. They called it philosopher’s wool, or nix alba (“white snow”). Today, we know the same thing as zinc oxide.

The name zinc, or something like it, was first documented by Paracelsus in the 16th century — who called it “zincum” or “zinken” in his book, Liber Mineralium II. The name might be derived from the German zinke, meaning “tooth-like” — because crystals of tin have a jagged, tooth-like appearance. But it could also suggest “tin-like”, since the German word zinn means tin. It might even be from the Persian word سنگ, “seng”, meaning stone.

These days, zinc is often used as a coating on other metals, to prevent corrosion.

P. M. de Respour formally reported that he had extracted metallic zinc from zinc oxide in 1668, although as I mentioned above, in truth it had been extracted centuries before then. In 1738, William Champion patented a process to extract zinc from calamine (a mixture of zinc oxide and iron oxide) in a vertical retort smelter, and Anton von Swab also distilled zinc from calamine in 1742.

Despite all that, credit for discovery of zinc usually goes to Andreas Marggraf, who’s generally considered the first to recognise zinc as a metal in its own right, in 1746.


Evidence of helium was first discovered during a solar eclipse.

Ironically for an element which is (controversially) used to fill balloons, helium’s discovery is easier to pin down. In fact, we can name a specific day: August 18, 1868. The astronomer Jules Janssen was studying the chromosphere of the sun during a total solar eclipse in Guntur, India, and found a bright, yellow line with a wavelength of 587.49 nm.

In case you thought this was going to be simple, though, he didn’t recognise the significance of the line immediately, thinking it was caused by sodium. But then, later the same year, Norman Lockyer also observed a yellow line in the solar spectrum — which he concluded was caused by an element in the Sun unknown on Earth. Lockyer and Edward Frankland named the element from the Greek word for the Sun, ἥλιος (helios).

Janssen and Lockyer may have identified helium, but they didn’t find it on Earth. That discovery was first made by Luigi Palmieri, analysing volcanic material from Mount Vesuvius in 1881. And it wasn’t until 1895 that William Ramsay first isolated helium by treating the mineral cleveite (formula UO2) with acid whilst looking for argon.

Mendeleev’s early versions of the periodic table, such as this one from 1871, did not include any of the noble gases (click for image source).

Interestingly, Mendeleev’s 1869 periodic table had no noble gases as there was very little evidence for them at the time. When Ramsay discovered argon, Mendeleev assumed it wasn’t an element because of its unreactivity, and it was several years before he was convinced that any of what we now call the noble gases should be included. As a result, helium didn’t appear in the periodic table until 1902.

Who shall we say discovered helium? The astronomers, who first identified it in our sun? Or the chemists, who managed to collect actual samples on Earth? Is an element truly “discovered” if you can’t prove you had actual atoms of it — even for a brief moment?


So far you may have noticed that all of these discoveries have been male dominated. This is almost certainly not because women were never involved in science, as there are plenty of records suggesting that women often worked in laboratories in various capacities — it’s just that their male counterparts usually reported the work. As a result the men got the fame, while the women’s stories were, a lot of the time, lost.

Marguerite Perey discovered francium (click for image source).

Of course, the name that jumps to mind at this point is Marie Curie, who famously discovered polonium and radium and had a third element, curium, named in honour of her and her husband’s work. But she’s famous enough. Let’s instead head over to the far left of the periodic table and have a look at francium.

Mendeleev predicted there ought to be an element here, following the trend of the alkali metals. He gave it the placeholder name of eka-caesium, but its existence wasn’t to be confirmed for some seventy years. A number of scientists claimed to have found it, but its discovery is formally recorded as having been made in January 1939 by Marguerite Perey. After all the previous failures, Perey was incredibly meticulous and thorough, carefully eliminating all possibility that the unknown element might be thorium, radium, lead, bismuth, or thallium.

Perey temporarily named the new alkali metal actinium-K (since it’s the result of alpha decay of 227Ac), and proposed the official name of catium (with the symbol Cm), since she believed it to be the most electropositive cation of the elements.

But the symbol Cm was assigned to curium, and Irène Joliot-Curie, one of Perey’s supervisors, argued against the name “catium”, feeling it suggested the element was something to do with cats. Perey then suggested francium, after her home country of France, and this was officially adopted in 1949.

A sample of uraninite containing perhaps 100,000 atoms of francium-223 (click for image source).

Francium was the last element to be discovered in nature. Trace amounts occur in uranium minerals, but it’s incredibly scarce. Its most stable isotope has a half life of just 22 minutes, and bulk francium has never been observed. Famously, there’s at most 30 g of francium in the Earth’s crust at any one time.

Of all the elements I’ve mentioned, this is perhaps the most clear-cut case. Perey deservedly takes the credit for discovering francium. But even then, she wouldn’t have been able to prove so conclusively that the element she found wasn’t something else had it not been for all the false starts that came before. And then there are all the other isotopes of francium, isolated by a myriad of scientists in the subsequent years…


All of which brings us to one of the last elements to be discovered: tennessine (which I jokingly suggested ought to be named octarine back in 2016). As I mentioned above, francium was the last element to be discovered in nature: tessessine doesn’t exist on Earth. It has only ever been created in a laboratory, by firing a calcium beam into a target made of berkelium (Bk) and smashing the two elements together in a process called nuclear fusion.

Element 117, tennessine, was named after Tennessee in the USA.

Like tennessine, berkelium isn’t available on Earth and had to be made in a nuclear reactor at Oak Ridge National Laboratory (ORNL) in Tennessee — the reason for the new element’s name. One of the scientists involved, Clarice E. Phelps, is believed to be the first African American to discover a chemical element in recent history, having worked on the purification of the 249Bk before it was shipped to Russia and used to help discover element 117.

Tennessine’s discovery was officially announced in Dubna in 2010 — the result of a Russian-American collaboration — and the name tennessine was officially adopted in November 2016.

Who discovered it? Well, the lead name on the paper published in Physical Review Letters is Yuri Oganessian (for whom element 118 was named), but have a look at that paper and you’ll see there’s a list of over 30 names, and that doesn’t even include all the other people who worked in the laboratories, making contributions as part of their daily work.

From five to many…

There’s a story behind every element, and it’s almost always one with a varied cast of characters.

As I said at the start, when we talk about discovering elements, our minds often leap to “who” — but they probably shouldn’t. Scientists really can’t work entirely alone: collaboration and communication are vital aspects of science, because without them everyone would have to start from scratch all the time, and humans would never have got beyond “fire, hot”. As Isaac Newton famously said in a letter in 1675: “If I have seen further it is by standing on the shoulders of giants.”

There’s a story behind every element, and it’s almost always one with a varied cast of characters.

This post was written by with the help of Kit Chapman (so, yes: it’s by Kit and Kat!). Kit’s new book, ‘Superheavy: Making and Breaking the Periodic Table‘, will be published by Bloomsbury Sigma on 13th June.

Like the Chronicle Flask’s Facebook page for regular updates, or follow @chronicleflask on Twitter. Content is © Kat Day 2019. You may share or link to anything here, but you must reference this site if you do. If you enjoy reading my blog, please consider buying me a coffee through Ko-fi using the button below.
Buy Me a Coffee at



Are we really wasting a valuable natural resource at parties?


This particular inert gas was discovered by an astronomer observing a solar eclipse.

A couple of weeks ago I wrote a (tongue in cheek) post about a very inert gas, nitrogen. Silliness aside though, nitrogen is a bit, well boring. I mean, we’ve known about it for nearly 250 years, it makes up nearly 80% of our atmosphere and it mostly just sits around doing nothing. Even plants, who’ve mastered the spectacular trick of making solid stuff out of sunlight and carbon dioxide, can’t do much with it in its gaseous form (with a few exceptions).

There are much more interesting inert gases. There’s one that wasn’t even discovered on Earth. In fact, it was first spotted on the Sun by Jules Janssen, an astronomer who was taking advantage of a total solar eclipse to study the Sun’s atmosphere. After some more experiments astronomer Norman Lockyer and chemist Edward Frankland named the element after the Greek word for the Sun. It was the first element to be discovered somewhere other than Earth.


Spectral lines of helium

As it turns out, this element is the second most abundant element in the universe (after hydrogen), but one of the least abundant elements on Earth – with a concentration of just 8 parts per billion in the Earth’s crust.

Today, almost all of us meet it as very young children. In balloons.

It’s helium, the second-lightest element in the periodic table and also, perhaps, the ultimate non-renewable resource.

Most of us meet this element as children.

We all learnt what ‘non-renewable’ means in school: it refers to something we’re using up faster than we can ever replace it. Almost anyone can tell you that crude oil is non-renewable. But the thing is, there are alternatives to crude oil. We can use bioethanolbiodiesel and their cousins to power vehicles and provide power. Bioethanol can act as a route to plastics, too. Scientists are also investigating the potential of algae to produce oil substitutes. These alternatives may (at the moment) be relatively expensive, and come with certain disadvantages, but they do exist.

We have no way to make helium. At least, no way to make it in significant quantities (it’s a by-product in nuclear reactors, but there we’re talking tiny amounts). And because it’s so light, when helium escapes into the atmosphere it tends to float, well, up. Ultimately, it escapes from our atmosphere and is lost. Every time you get fed up with that helium balloon that’s started to look a bit sorry for itself and stick a pin in it (perhaps taking a few seconds to do the squeaky-voice trick first) you’re wasting a little bit of a helium.

But so what? We could all live without helium balloons right? If we run out, balloons will just have to be the sinking kind. What’s the problem?

Liquid helium is used to cool the magnets in MRI machines.

Liquid helium is used to cool the magnets in MRI machines.

The problem is that helium has a lot more uses than you might realise. Cool it to -269 oC – just 4 degrees warmer than absolute zero, the lowest termperature there is – and it turns into a liquid, and that liquid is very important stuff. It’s used to cool the superconducting magnets in MRI (magnetic resonance imaging) scanners in hospitals, which provide doctors with vital, non-invasive, information about what’s going on inside our bodies. MRI techniques have made diagnoses more accurate and allowed surgery to become far more precise. Nothing else (not even the lightest element, hydrogen) has a lower boiling point than helium, so nothing else is quite as good for this chilly job. Scientists are working hard on developing superconducting magnets that work at warmer temperatures, but this technology is still in its infancy.

There’s another technology called NMR (nuclear magnetic resonance) which chemists use all the time to help them identify unknown compounds. In fact, MRI was born out of NMR – they’re basically the same technique applied slightly differently – but the medical application was renamed because it was felt that patients wouldn’t understand that the ‘nuclear’ in NMR refers to the nuclei of atoms rather than nuclear energy or radiation, and would balk at the idea of a ‘nuclear’ treatment. Possibly imagining that they’d turn into the Hulk when they went into the scanner, who knows.

Since it works in essentially the same way, NMR also relies on superconducting magnets, also often cooled with liquid helium. Without NMR, whole swathes of chemical research, not to mention drug testing, would run into serious problems overnight.

It doesn’t stop there. Helium is also used in deep-sea diving, in airships, to cool nuclear reactors and certain other types of chemical detectors. NASA also uses massive amounts of helium to help clean out the fuel from its rockets. In summary, it’s important stuff.

But if we can’t make it, where does all this helium come from?

The Earth’s helium supplies have largely originated from the very slow radioactive alpha decay that occurs in rocks, and it’s taken 4.7 billion years to build them up. Helium is often found sitting above reserves of natural oil and gas. In fact that’s exactly how the first helium reserve was discovered: when, in 1903, an oil drilling operation in Kansas produced a gas geyser that wouldn’t burn. It turned out that although helium is relatively rare in the Earth overall, it was concentrated in large quantities under the American Great Plains.

The National Helium Reserve

Show me the way to… The National Helium Reserve

Of course this meant that the United States quickly became the world’s leading supplier of helium. The US started stockpiling the gas during World War I, intending to use it in barrage balloons and later in airships. Helium, unlike the other lighter-than-air gas hydrogen, doesn’t burn. This made things filled with helium safer to handle and, of course, more difficult to shoot down or sabotage.

In 1925 the US government set up the National Helium Reserve in Amarillo, Texas. In 1927 the Helium Control Act came into force, which banned the export of the gas. At that point, the USA was the only country producing helium, so they had a complete monopoly (personally, I’d quite like to see a Monopoly board with ‘helium reserves’ on it, wouldn’t you?). And that’s why the Hindenburg, like all German Zeppelins, both famously and tragically had to use hydrogen as its lift gas.

Helium use dropped after World War II, but the reserve was expanded in the 1950s to supply liquid helium as a coolant to create hydrogen/oxygen rocket fuel during the Space Race and the Cold War. The US continued to stockpile helium until 1995. At which point, the reserve was $1.4 billion in debt. The government of the time pondered this and ended up passing the Helium Privatization Act of 1996, directing the United States Department of the Interior to empty the reserve and sell it off at a fixed rate to pay off the cost.

Right now, anyone can buy cheap helium in supermarkets and high street shops.

Right now, anyone can buy cheap helium in supermarkets and high street shops.

As a result cheap helium flooded the market and its price stayed fairly static for a number of years, although the price for very pure helium has recently risen sharply. This sell-off is why we think of helium as a cheap gas; the sort of thing you can cheerfully fill a balloon with and then throw away. Pop down to a large supermarket or your local high street and you might even be able to buy a canister of helium in the party section relatively cheaply.

The problem is that this situation isn’t going to last. The US reserves have been dramatically depleted, and at one point were expected to run out completely in 2018, although other reserves have since been discovered and other countries have set up extraction plants. It is also possible to extract helium from air by distillation, but it’s expensive – some 10,000 times more expensive. None of these alternatives are expected to really ease the shortage; they’ll just delay it by a few years.

So are helium party balloons truly an irresponsible waste of a precious resource? Well… the helium that’s used in balloons is fairly impure, about 98% helium (mixed with, guess what? Yep, we’re back to nitrogen again!) whereas the helium that’s needed for MRI and the like is what’s called ‘grade A’ helium, which is something like 99.997% pure, depending on whom you ask. Of course you can purify the low-grade helium to get the purer kind but this costs money, which is why grade A helium is so much more expensive.

NABAS logo

The National Balloon Association (‘the voice of the balloon industry’ – you can’t help wondering whether that’s a very high-pitched voice, can you?) argues that balloons only account for 5-7% of helium use and that the helium that goes into balloons – which they prefer to call ‘balloon gas’ because of its impurities – is mainly recycled from from the gas that’s used in the medical industry, or is a by-product of supplying pure, liquid helium, and therefore using it in balloons isn’t really a problem.

Dr Peter Wothers argues that helium balloons should be banned.

Dr Peter Wothers argues that helium balloons should be banned.

On the other hand, more than one eminent physics professor has spoken out on the subject of helium wastage. It costs about 30-50p to fill a helium balloon, but Professor Robert Richardson of Cornell University argued (before his death in 2013) that a helium party balloon should cost £75 to more accurately reflect the true scarcity value of the gas. Dr Peter Wothers of Cambridge University has called for an outright ban of them, saying that in 50 years’ time our children will be amazed that we ever used such a precious material to fill balloons.

Is it time to call for a helium balloon boycott? Perhaps, although it will probably take more than one or two scientifically-minded consumers refusing to buy them before we see any difference. Realistically, the price will sky-rocket in the next few years and, as Peter Wothers suggests, filling balloons with helium will become a ridiculous notion because it’s far too expensive.

Will images like this make no sense in the future?

Will images like this make no sense in the future?

It’s strange to think though, that in maybe 50 years or so the idea of a floating balloon might simply disappear. Just think of all the artwork and drawings that will no longer make sense.

Perhaps this quotation by the late Sir Terry Pratchett is even more relevant than it first appears:

“There are times in life when people must know when not to let go. Balloons are designed to teach small children this.”


Follow The Chronicle Flask on Facebook and Twitter to hear about the latest blog posts and to discover other interesting sciencey tidbits from around the internet.