Day 98: Chlorine

^{Clockwise from left: a nice flask of chlorine (from Wikimedia Commons), chlorine’s disinfectant abilities creates a famous smell in swimming pools (from Wikimedia Commons), chlorine as it appears in the periodic table.}

Today we will cover the last of the “classical” halogens, chlorine. There is one more element that is technically a halogen, but that is a matter for tomorrow…

Chlorine is a gas at room temperature, and a pretty unpleasant one at that. Like the other halogens, chlorine atoms have a nearly full outer shell of electrons, meaning they really want to react with other atoms to gain one more electron for its outer shell. This high reactivity of chlorine gas means it will burn the skin, eyes or respiratory system if it comes in contact with it, so best avoid it.

The atomic structure of chlorine. The outer ring only has 7 electrons in it when the maximum is 8, so the chlorine atom will strive to react with another element to gain just one more electron. Adapted from Wikimedia Commons.

Even though chlorine sounds like the kind of element you want to stay well away from, in it’s ion form called chloride (where it has gained an electron in its outer shell and so is negatively charged) it is in fact an essential element for life. From the posts on sodium and potassium, which have positively charged ions, we know that charge across a cell membrane plays an important role in sending signals between cells and even down nerves. As a negatively charged ion chloride can give the body much more control over this charge, as it can act to counter positive charges or even enhance the difference in charge across a cell membrane by having negative chlorides on once side and positive sodium or potassium on the other side. Hydrochloric acid, which has the formula HCl, is also the acid found in the stomach which aids in digestion and fighting pathogens that we’ve consumed. So chlorine can be both evil and good for us, just depends on the context. Breathing chlorine gas- no. Eating sodium chloride (salt) on your food- fine.

^{Chlorine is an essential element in humans, as it is needed for gastric acid in your stomach (left; Needpix), and for sending electrical pulses down your neurons (right; Wikimedia Commons) through the movement of negatively charged chloride ions.}

Although chlorine has been around in various forms since around 6,000BC, the identification and naming of the element did not occur until the 19th century. The earliest use of chlorine was through salt (sodium chloride) as a preservative in rock form and brine. In around the 9th century AD aqua regia (“Royal water”) started appearing in alchemy records, which was a mixture of hydrochloric acid (known at the time as muriatic acid) and nitric acid that could dissolve fancy metals like gold and platinum (hence the name). The reaction would often give off chlorine gas, but wasn’t recognised properly until the 17th century.

A test tube of aqua regia showing some gold who’s the real king. From Wikimedia Commons.

Even the characterisation of many of chlorine’s properties was performed before it was established as an element. Carl William Scheele, a Swedish chemist, produced chlorine gas and noted its deadly effects, greeny yellowy colour, and pungent smell. He gave it the snappy name “dephlogisticated muriatic acid air” because it was a gas (air) that smelled like aqua regis (muriatic acid). The “dephlogisticated” bit was due to oxygen being in his gas sample, and we’ll cover the phlogiston theory more with the post on oxygen (basically it is a wrong idea about what oxygen is).

It came down to our 19th century elemental discovery friend Sir Humphry Davy to finally crack the chlorine code in 1810. He repeated experiments performed the year before where chemists tried to decompose this gas and failed, and after he too failed to decompose it he declared it a new element. He named the element chlorine using the Greek “chlōros” (χλωρος), which means “green-yellow”, due to the colour of the gas. The “-ine” suffix has stuck for all the elements in the halogen group (group 17 on the periodic table), and even the word “halogen”, meaning “salt-producer”, came about the year after to describe chlorine’s ability to create salts in reactions.

So apart from in our bodies and table salt, what do we use chlorine for? Well unsurprisingly given its rather aggressively reactive properties, chlorine has a long history of use as a disinfectant. It is very effective at killing pathogens, hence why locations such as swimming pools use chlorine to keep its water clean. That distinctive “chlorine” smell you get at swimming pools is actually the scent of chloramine, a substance caused when dissolved chlorine in the water has reacted with amines, which are a common group of compounds found in life. Most bleach that one can find in the home contains chlorine, although to ensure the nasty chlorine gas doesn’t reach people’s lungs it usually takes the form of a hypochlorite ion (CIO^–), which will only release the chlorine when necessary. These hypochlorte treatments are also used to clean drinking water.

Bleach uses chlorine to destroy nasty germs to keep your bathrooms and surfaces clean! From Wikimedia Commons.

A lot of chlorine is also used to make one of the most common plastics: polyvinyl chloride (PVC). This plastic is a polymer- a string of identical small molecules (monomers) bonded together many many times over. The monomer for PVC is called vinyl chloride (C₂ClH₃). PVC is an incredibly versatile plastic, being used in construction (pipes, doors and windows), packaging, credit cards, bottles, waterproof clothing, medical packaging and plastic signs. A big disadvantage of PVC however is that it is not widely recycled, meaning that a lot of issues with plastic waste are due to landfill PVC. So it is not the most environmentally friendly of substances.

Plastic waste through improper disposal of PVCs is an issue that needs to be tackled effectively now. From Wikimedia Commons.

And unfortunately the environmental hazards of chlorine compounds does not stop at plastics. The halocarbons are a controversial group of chemicals that involve a carbon atom bonded to various halogens. We’ve already covered the ozone-depleting chlorofluorocarbons (CFCs) in the fluorine post, which contain chlorine, but there are also carbon tetrachlorides, which have a similar effect on the environment. Carbon tetrachlorides were also used as refrigerants and in fire extinguishers, including the “Red Comet”, a glass bulb containing carbon tetrachloride that was thrown grenade-like at a fire. It would smash on impact, releasing the tetrachloride into the surrounding air to deprive the fire of oxygen. Carbon tetrachlorides are now banned due to effects on the ozone layer and on humans through damaging nerves, liver, kidneys and as a carcinogen.

The mysterious red comet, where the broken glass produced would be the least of your worries. From Wikimedia Commons.

And that’s chlorine: the environmentally unfriendly, greeny yellowy, gastric element!

Day 97: Rhodium

^{Clockwise from left: a rose, inspiration for the name rhodium (from Pixabay); rhodium as it appears on the periodic table; a round lump of rhodium (from Wikimedia Commons).}

We have a double-billing of platinum group elements: following on from yesterday’s ruthenium is today’s rhodium. So we have another inert, robust, shiny transition metal that can be found in platinum ores.

The discovery of rhodium falls to English chemist William Hyde Wollaston in 1803. He dissolved platinum ore in aqua regis (a common way to discover platinum group elements) before subjecting the mixture to sodium hydroxide (to neutralise the acid), ammonium chloride (to remove the platinum), zinc (which precipitated any copper, lead, palladium and rhodium), nitric acid (to dissolve everything except palladium and rhodium) and then aqua regis again (to dissolve the palladium but not rhodium). After that long list of chemicals Wollaston finally added sodium chloride to the mixture to remove the rhodium as rhodium chloride. Rhodium chloride has a rose-red colour to it, leading to Wollaston naming the element after the Greek “rhodon” (ῥόδον), meaning “rose”.

The “rose-coloured” rhodium chloride. Perhaps this is just bad lighting? From Wikimedia Commons.

The uses of rhodium will ring a few bells with anyone who has been keeping up with my latest posts. The main use of rhodium by far is in catalytic converters, devices attached to car exhausts that help convert more dangerous gases produced by combustion engines into something relatively safer. The rhodium part of the catalytic converter works to reduce (add electrons to) nitrogen oxides (which cause damage to lungs), converting them into safer nitrogen and oxygen molecules. Rhodium’s catalytic uses also extend to making chemical industries, being used to make nitric and acetic acid.

Is it me or has every other element article this last week involved catalytic converters? From Flickr.

Rhodium’s reflective properties have been taken advantage of in coating optic fibres (for faster internet), optic mirrors (for spectrophotometers and solar panels) and headlight reflectors. The thermostability of rhodium has also led to its use in crucibles, which are vessels exposed to high temperatures for example in smelting, and thermocouple elements, which are temperature-sensing elements found in ovens that create a voltage depending on the temperature it is currently exposed to. So rhodium is with you from the moment you drive home, put your food in the oven and sit back streaming Netflix.

Headlight reflectors are what helps all that light from the bulb to point in a certain direction. From Wikimedia Commons.

Rhodium has also gained some aesthetic uses. “Rhodium flashing” is when rhodium is plated on white gold or platinum jewellery, which gives it a temporary extra shiny surface until it wears off. Rhodium’s rarity has also given it a new status as representing something higher in achievement than bronze, silver, gold or even platinum. A rather wonderful example of this was when Paul McCartney of the Beatles was given a rhodium-plated record by Guinness World Records for being the best selling songwriter and artist of all time. The British crown jewels also contain rhodium-plated components.

Paul McCartney and Linda McCartney accepting Paul’s rhodium record from the Guinness World Records. From paimages.co.uk.

And that’s rhodium- the automobile-essential, better than 1st place and rose-tinted element!

Day 96: Ruthenium

^{Clockwise from left: a dark shiny lump of ruthenium (from Wikimedia Commons), ruthenium as it appears in the periodic table, ruthenium-platinum alloy ring with a topaz in it (from Qevon.com).}

Ruthenium is an element that is really up and coming in terms of applications, which comes as quite a respite after all this talk of elements being phased out for being dangerous. Being another member of the prestigious platinum group, ruthenium is relatively inert and found largely in platinum ores.

The discovery and naming of ruthenium falls to the combined efforts of Swede Jöns Berzelius, German Gottfried Osann and Baltic German Karl Ernst Claus. Berzelius and Osann dissolved platinum in the acidic mixture known as aqua regia in 1829, and although Berzelius claimed to have not found any new elements in the residues left after dissolving, Osann believed he found three elements. The platinum was found in the Russian part of the Ural Mountains, and therefore Osann named these new elements pluranium, ruthenium (from the latin Ruthenia, which was the area now consisting of West Russia, Belarus, Ukraine and Eastern Slovakia and Poland) and polinium. Berzelius and Osann never agreed on this, and Osann’s failure to repeat the experiment led him to drop the case.

A platinum coin being dissolved in aqua regis, a rather intense mixture of nitric and hydrochloric acid capable of dissolving noble metals. From Wikimedia Commons.

But this is where Claus comes in, specifically in 1844. Platinum was being used at the time to make the currency roubles, and Claus managed to isolate ruthenium from residues used in rouble production. Both out of respect for Osann and for his country, Claus kept the name ruthenium for his discovery.

Now onto the up and coming uses for ruthenium. Firstly its inertness and high toughness, ruthenium has gained a novel use in coating electrical contacts, effectively two pieces of conductive metal that are brought together to complete a circuit. It is also cheaper than the prior material rhodium. Another electrical use for ruthenium is in chip resistors, where ruthenium dioxide is mixed with lead or bismuth to make components that oppose the flow of electrons through a circuit, which helps to protect or control them. Some ruthenium chemicals are also able to absorb light, which has led to research into their use in cheaper solar panels.

Ruthenium can often be found in resistors in electrical circuits. From PxFuel.

Alloys of ruthenium with other members of the platinum group have also led to some useful applications. The hardness and heat resistance of ruthenium has allowed for its inclusion in superalloys (alloys that can function even at extremely high temperatures) that have been used in jet engines. Some fountain pen nibs also contain a ruthenium alloy for its inertness and toughness. Finally, alloying ruthenium with platinum has led to some very nice dark silver coloured jewellery.

Fountain pens often have a ruthenium alloy in their tip. From Wikimedia Commons.

One final, quite interesting use of ruthenium is through one of its compounds, ruthenium tetroxide. This chemical reacts with fatty oils to produce a brown black colour (made of ruthenium dioxide), and therefore are getting used for fingerprint detection!

Ruthenium tetroxide is gaining use as a fingerprint detector! From clpex.com.

And that’s ruthenium- the Russian, superalloyed and crimefighting element!

Day 95: Hafnium

^{Clockwise from left: a lumpy lump of hafnium (from Wikimedia Commons); the city of Copenhagen, or as it is in Latin, Hafnia (from Wikimedia Commons); hafnium as it appears in the periodic table.}

I’m going to tell you now that this is another element named after a Scandinavian location, but now Denmark gets a little credit. More specifically the capital city of Denmark, Copenhagen, or as it is known in Latin- Hafnia.

It may come as a real shock that the discovery of hafnium occurred in Copenhagen in 1923. Despite being predicted by Dmitri Mendeleev in 1869, hafnium was a sneaky element as it is a difficult element to separate from a similar element zirconium. It was finally achieved though by Dutch physicist Dirk Coster and Hungarian chemist Georg von Hevesy at the University of Copenhagen, who used a technique called x-ray spectroscopy to find hafnium in the mineral zircon. X-ray spectroscopy is when atoms in a sample are excited by being hit by some energy (often a specific wavelength on the electromagnetic spectrum) and the range of x-ray wavelengths given off when the atom releases that energy is different depending on the element of that atom. A unique spectrum of x-rays given off the zircon flagged to Coster and Hevesy that there was a new element in there. In naming the element after Copenhagen it is thought they may also have been honouring the Danish physicist Niels Bohr.

Zircon’s secret: a small amount of hafnium hiding inside! From Wikimedia Commons.

Hafnium’s similarity to the more common zirconium puts it at a slight disadvantage when it comes to uses. However it does have applications out there. Hafnium is rather good at absorbing neutrons without splitting, and therefore are often used in nuclear reactor control rods. These are rods that help absorb the neutrons being sent out by uranium or plutonium splitting during nuclear fission, which helps ensure the reaction doesn’t get out of control.

Hafnium also has a nice high melting temperature (around 2,233°C). This has led to its use in high temperature uses like plasma welding and cutting, and alloys of hafnium with metals like niobium and titanium are often used in spacecraft, for example the thruster nozzles on the Apollo Lunar Modules.

The Apollo 11 Lunar Module would have had hafnium in it for temperature resistance. From Pixabay.

Finally, the chemical hafnium oxide has use in electronics as an insulator. These insulators can be found in various microprocessors within integrated circuits, meaning that there’s a good chance that your computer or laptop has a little bit of hafnium in it.

And that’s hafnium- the moon exploring, Danish and controlling element!

Day 94: Fermium

^{Clockwise from left: a very blurry photo of Enrico Fermi (from Wikimedia Commons), an alloy of fermium and ytterbium containing 0.00004% fermium used to determine some of the characteristics of fermium (from By Ben E. Lewis through Wikimedia Commons), fermium as it appears on the periodic table.}

We haven’t quite reached 100 posts, but we have reached the 100th element: fermium! At this point you know the drill: it’s a synthetic heavy element named after a famous scientist and with no applications outside research. The most stable isotope of fermium out there has a half-life of 100.5 days, so researchers have a little more time to work on it than some of the superheavy elements.

The discovery of fermium is a little more unique than a lot of the other transuranic elements. Like einsteinium, element 100 was found after the Ivy Mike nuclear test in 1952, but unlike einsteinium, this element was going to be a lot rarer as it is a larger atom. So after einsteinium was found and the concept of these new elements being created was formed in scientists’ minds, coral from the test site at the Enewetak atoll were analysed in Berkeley, US. From this element 100 was separated, but because of the Cold War being in full swing at the time this discovery was kept a secret. Instead the team at Berkeley, headed by Albert Ghiorso, managed to make element 100 by bombarding plutonium with neutrons. This data was published in 1954, a year before the Ivy Mike business was declassified.

The Enewatak atoll, the location of the Ivy Mike hydrogen bomb tests. From NASA via Wikimedia Commons.

The element was named after Enrico Fermi, an Italian physicist and “architect of the atomic bomb”. So I guess it fits that an element first created by a nuclear weapon was named after him, even though after the first hydrogen bomb tests Fermi strongly opposed further development of these explosives. His work on using neutron bombardment to create radioactive substances earned him the Nobel prize in 1938, but it was after he had fled to the United States with his Jewish wife to escape Italian anti-Semitic racial law that his architecture status comes in. He became part of the Manhattan Project, and developed the first every artificial nuclear reactor, Chicago Pile-1. The reactor used uranium fission from neutron absorption to start a chain reaction whereby the neutrons released of one atom splitting whack into another atom and causes that to split too. For a nuclear reactor to work, what is called criticality needs to be achieved- effectively when the rate of neutrons being produced in the reaction is larger than the neutrons being lost due to leakage or otherwise. When criticality is reached neutrons no longer need to be fired into the reactor, and it becomes self-sustaining. Chicago Pile-1 reached this state in 1942, and from that the nuclear reactor was born.

The earliest nuclear reactors like the Chicago Pile-1 were effectively big structures of graphite bricks, which were designed to decrease the speed of any neutrons trying to escape. From atomicheritage.org,

And that’s fermium: a coral-destroying, critical and Italian element!

Day 93: Carbon

^{Clockwise from left: a lump of graphite (from Wikimedia Commons), a fancier lump of diamond (from Wikimedia Commons), carbon as it appears in the periodic table.}

When I started this blog a few elements popped into my head as “potentially big posts if I didn’t control myself”. Carbon was the first to do so, as a biochemist where carbon is such a common element we don’t even bother to write it in chemical drawings any more. But let’s see what happens.

A chemical representation (left) and a ball and stick model (right) of the chemical methane. Carbon (C, black) likes to form bonds with four other atoms (hydrogens here, H, white) in a triangular pyramid (tetrahedron) formation. Don’t worry to much about the weird dashed and blocky lines between the right hand hydrogens: that is just a way of drawing in chemistry to make the picture look more 3D, with the dashed triangle meaning it is further back and the block triangle meaning it is coming forward. The angle pointed out in red just shows that each angle in this structure from hydrogen to carbon to hydrogen again are the same.

One thing that we should start off with for carbon is that it is the famous example of different allotropes in chemistry. Allotropes are different structural arrangements for the atoms of an element which often have quite different properties. The most famous forms of carbon are diamond (where a very repetitive and interconnected arrangement of carbon atoms leads to a very strong and colourless substance) and graphite (where carbon atoms bond together to form hexagonal “sheets” which can slide over each other easily). The interesting thing about these forms is that diamond does not conduct electricity, but graphite can, and it all comes down to how the carbon atoms bond together. Carbon ideally wants to bond with 4 other atoms in a triangular pyramid formation (often called a tetrahedron), and achieves this with diamond. However in graphite the carbons only bond with three other atoms, leaving those electrons that would form the 4th bond left to float around the graphite freely, and it’s these free electrons that allow current to flow through the substance.

The structures of graphite and diamond. As you can see the carbons each bond to three other carbon atoms, forming sheets of hexagons (there are only two here but imagine more), and they are loosely connected to other sheets (dotted lines) but not rigidly. If you look closely at the diamond on the other hand, you’ll see that those carbons bond four other carbons, creating this rigid and stable structure of tetrahedrons. From Wikimedia Commons.

Other than graphite and diamonds, other common allotropes of carbon exist. The rather broad term “amorphous carbon” refers to carbon with no kind of regular structure, which includes coal and soot. There are also synthetic allotropes of carbon that we have made for a specific purpose, like carbon fibre, glassy carbon (a very hard and heat resistant form of carbon used in crucibles and electrodes) and nanocarbons.

Carbon has been known about for an incredibly long time. Soot, coal and charcoal have been known about since before anyone wrote anything down (prehistory) and there is evidence of diamonds in China in around 2,500 BC. The word carbon derives for the latin for coal/charcoal: carbo, and it came down to the French to determine carbon as a new element in the 18th century. Antione Lavoisier showed that when you burn diamonds and charcoal carbon dioxide was released in a way proportionate to the amount burned. Chemists Claude Louis Bethollet, Gaspard Monge and C. A Vandermonde then performed similar experiments burning graphite to the same effect, and in their publication put forward “carbone” as its potential name.

I felt I went a bit too far with all those structural diagrams so here’s an apology piece of coal. From Wikimedia Commons.

The uses of carbon and carbon-based substances make a long list, so here are some highlights. Coal and hydrocarbons (chemicals that just consist of hydrogen and carbon) are often used as fuels, although the greenhouse gas carbon dioxide being released and subsequent climate change has led to attempts for these substances to be phased out. Hydrocarbons can also be polymerised- aka many identical smaller chemicals being bonded together to make one long chain- in the creation of plastics. Graphite is common in pencils (originally graphite was thought to be a form of lead, hence the term “pencil lead”) and as conductive brushes in motors that allow electricity to transfer from stationary to rotating wires. Diamonds being the hardest natural substance on Earth has gained use not only in jewellery but in tools and industrial applications, coating drills and blades to make them more durable.

A scientific misunderstanding of graphite is why the pencil has a “lead”. From Wikimedia Commons.

Activated carbon, also known as activated charcoal, is a form of charcoal that is created using exposure to acids, bases, salts or hot gases which creates many tiny pores. These tiny pores increase the surface area of the charcoal for chemical reactions and adsorption of gases, which has given activated charcoal many uses in industrial purification, treating poisoning or overdoses in medicine, purifying air of certain gases and filtering vodka or whiskey to purify them.

Nanocarbons are effectively new formations of carbon that can fit a specific purpose. They are structures on the nano scale, hence the name, and the most famous forms are nanotubules and buckminsterfullerenes. Carbon nanotubes are exactly what you expect: tiny tubes made of a mesh of carbon atoms. They are incredibly strong and conduct electricity, and currently have some niche uses (for example in some very fancy bike components and as scaffolding for bone growth in medicine), but research is continuing and if there are cheaper ways to make the little tubes then more applications in structure and electronics may be inbound! Buckminsterfullerenes (named after Richard Buckminster Fuller, the inventor of the structures) are effectively the same mesh of carbons as used in nanotubes, but instead forming a ball or ellipsoid (squashed ball). These “bucky balls” have potential applications in medicine as deliver antibiotics to bacteria and attack cancer cells. So it might be worth keeping an eye out for these tiny structures!

^{Nanocarbons such as buckminsterfullerene (left) and carbon nanotubes (right) may be the future of medicine, industry and electronics. From Wikimedia Commons.}

We couldn’t talk about the element of life without biology. Carbon can form bonds with many other elements, meaning it is very versatile, and its ability to form up to four bonds in various directions gives it much structural variability. All the biological molecules out there: lipids (fats), DNA, proteins, sugars (carbohydrate means “hydrated carbon”, or a chemical where for every carbon atom there is a water molecule: two hydrogens and an oxygen) and metabolites all have carbon in their structure, with other elements attached giving them various functions. Think of carbon like the skeleton: it’s key to holding everything together. No wonder that the function of the most important reaction in life- photosynthesis- is to capture carbon dioxide from the atmosphere and convert it into chemicals that can be used by pretty much every organism out there. There is a term for the study of carbon-based chemicals: organic chemistry, and when chemists talk about organic substances they are usually talking more about carbon-based chemicals than crops with lower pesticide use and less intensive farming methods. I don’t know if I’ve made this point clear, but without carbon life would not exist.

^{Sorry about one more chemical structure dump: but this is to highlight just how crucial carbon is. These chemicals are all essential to life: DNA (top left), lipids (top right), sugars (middle right) and amino acids (bottom) which make up proteins all contain carbon. In fact, in all these structures wherever you see an unlabelled angle or line that just ends, those are all carbon atoms; we are just too lazy to label them all because there are so many (I mean look at those long chains in the lipids)!}

And that’s carbon: more than just coal, pencils and diamonds, it’s crucial to all of us!

Day 92: Curium

^{Clockwise from left: Marie Curie, namesake of curium (from Wikimedia Commons); curium as it appears on the periodic table; Sojourner, a Mars Rover that uses curium in specialised spectrometers to analyse samples (from Wikimedia Commons).}

I’m not going to lie to you all: this is another transuranic synthetic element named after a pioneering physicist. And spoilers: there’s more to come! But for now here’s the second of only two elements named after women: curium. This disproportion needs to change.

Curium was discovered, by which I mean synthesised, by Glenn Seaborg and the gang at the University of California in 1944. Like all the elements created by the cyclotron during the second world war, it was kept a secret until afterwards when Seaborg revealed its discovery on a children’s TV show (see the americium post for that story). Plutonium was bombarded with alpha particles (aka helium nuclei) to make the heavier element.

The element was of course named after Marie Curie and her husband Pierre. Marie was the first woman to win the Nobel prize for creating the theory of radioactivity, and in fact creating the word radioactive (a combination of “radiation” and “actif”, the French for active). After Henri Becquerel had found that uranium was emitting rays that penetrated through solid objects, Curie decided to look into this further. She found that using an electrometer (that measures charge) showed the rays coming from uranium caused the surrounding air to become conductive, and crucially that this was in proportion to the amount of uranium present. This led her to suggest that the radiation was coming from the atoms.

Curie’s work on the uranium minerals pitchblende and torbernite led her to realise that the difference in radiation coming from the substances meant more radioactive elements were in them. Through this she concluded that thorium was radioactive, and found the elements polonium and radium. It was the discovery of these elements that earned her her second Nobel Prize, making her the only woman to have received two Nobel Prizes.

One of Marie Curie’s notebooks, which are still so radioactive that they are kept in lead boxes in the Bibliotheque National in France. From the Wellcome Library through ScienceAlert.com.

Mary Curie was of course riddled with radioactivity throughout her life, as the dangers of ionising radiation had not been discovered yet. Her work on radioactive elements and her world war 1 radiography work assisting battlefield surgeons with mobile radiography machines (wonderfully called petites Curies, “little Curies”) meant that her death came as a result of aplastic anaemia from radiation, meaning her body just couldn’t produce enough blood cells. When both Curie and her husband were transferred to the crypt of the Paris Panthéon (a crypt for national treasures where the likes of Louis Braille, Napoleon and Voltaire have been buried) in 1995, they had to be put in lead-lined coffins due to their bodies still being intensely radioactive! Her papers and notebooks are also stored in lead boxes due to their dangerous levels of radioactivity.

Marie Curie’s lead-lined tomb in the Paris Panthéon. She was the first woman to be included in this French honourable crypt. From Wikimedia Commons.

Unlike a lot of the transuranic elements, curium does have some applications! Curium isotopes curium-242 and curium-244 are both used in radioisotope thermoelectric generators whereby radioactivity is converted to electricity and then heat energy. This form of warmth is what has been used on various spacecraft to keep them cosy out in space. Certain spectrometers can use the scattering of the alpha particles emitted from curium to identify chemical compositions of samples, called alpha particle x-ray spectrometer. These special machines are how Mars rovers can identify samples whilst all the way out on the red planet.

And that’s curium: the pioneering, radioactive and thermoelectric element!

Day 91: Erbium

^{Clockwise from left: a shiny lump of erbium (from Wikimedia Commons), erbium can help with fibreoptic cables (from Wikimedia Commons), erbium as it appears in the periodic table.}

We have reached the 3rd in the quadrilogy of Ytterby: erbium. This element is actually helping you all read this, but more on that later.

First we have that origin story once more, with Carl Gustaf Mosander, Swedish chemist who was working on the mineral gadolinite in 1843. Upon obtaining what he thought was pure yttria (yttrium oxide) from the rock, he found two contaminants, which were the oxides of erbium and terbium. He named these oxides erbia and terbia, referencing Ytterby, the Swedish village where the gadolinite came from. Fun extra fact though: the names for these new elements were swapped around a few decades later when a researcher accidentally swapped the labels on them whilst working. So technically erbium is terbium and vice versa, which is just adding to the confusing names!

The pier (brygga) in Ytterby, namesake of erbium. From Wikimedia Commons.

Erbium’s uses are slightly limited by the fact it reacts with water and very easily tarnishes when exposed to air. However when alloyed with vanadium erbium can make the resultant metal very malleable and easily worked. Combining nickel with erbium creates an alloy with a very high heat capacity (i.e. it takes more energy to raise its temperature), thus leading to its use in applications where low temperatures are necessary, like cryocoolers (very low temperature fridges).

Erbia has the ability to absorb infrared radiation, which has led to its use in safety glasses for welders and metallurgists. This glass gains a nice pink colour, which has also been used to colour sunglasses, in photographic filters and for making cheap jewellery through colouring cubic zirconia.

Erbium glass is very useful for protecting against infrared, but also quite pretty. From Wikimedia Commons.

The final big use of erbium is in fibre optic cables. Erbium is added to glass fibres made of silica (it is said to be “doped” with erbium), which allows the glass fibre to absorb light at one frequency and then emit light at another frequency. This allows the light being pumped into the fibre to be amplified in the wire as the erbium absorbs energy and re-emits it at the right wavelength. Effectively erbium is making our internet connection very fast indeed!

And that’s erbium: an optical, Ytterbian, pink element!

Day 90: Livermorium

^{Clockwise from top-left: the city of Livermore and location of livermorium’s discovery (from Wikimedia Commons); Robert Livermore, rancher and landowner whose land became the city of Livermore (from the Livermore Heritage Guild through Wikimedia Commons); livermorium as it appears on the periodic table.}

Another element that was synthesised in my lifetime, livermorium was first created in the year 2000. You will all be unsurprised to hear that there is not an awful lot of applications for this element, as it is superheavy and does not stick around long (the most stable isotope has a half life of 60 milliseconds). But hey, it’s an element so here’s a slightly shorter post on livermorium.

Element 116 was first attempted in the 1970s and continued right through the remainder of the 20th century. The experiments usually involved curium being bombarded with calcium, and were happening in the United States at the Lawrence Livermore National Laboratory, at the Joint Institute for Nuclear Research in the Soviet Union/Russia, and at GSI in Germany. Things started to pick up in 1990 when the labs began collaborating more after the Transfermium Wars, with more intense forms of calcium bombardment being invented and put to use.

After some unconfirmed claims of producing element 116, the breakthrough came through in 2000 at JINR. The curium bombardment with calcium led to one atom of element 116 being made. Experiments to confirm this continued through 2001-2006, with more isotopes of element 116 being made, and the number of atoms being produced still miniscule (around 12 including that first one in 2000). Finally in 2011, IUPAC concluded that over the last decade, element 116 had truly been discovered and the name livermorium was given to honour the Lawrence Livermore National Laboratory in Livermore, California. JINR apparently were calling for moscovium originally, but that got given to element 115 instead. In a sort-of cheating way, this element was kind of named after Robert Livermore, who was the landowner that owned the land that became the city of Livermore in the 19th century.

An aerial photograph of the Lawrence Livermore National Laboratory in California. From energy.gov.

And that’s livermorium: the result of cross-continental collaboration and named after an old rancher!

Day 89: Lawrencium

^{Left: a photograph of name inspirer Ernest Lawrence (from the Nobel foundation through Wikimedia Commons). Right: lawrencium as it appears in the periodic table.}

Once again we return to the bottom of the periodic table. Synthetic radioactive heavy element? Check. Named after an eminent scientist? Check. Does not last long enough for there to be uses outside the lab? Check (the most stable form of lawrencium has a half life of 11 hours). Controversial discovery story acting as a metaphor for the cold war? Check!

Lawrencium is the final actinide element that had claimed discoveries across the 1950s, 60s and 70s from both the United States (at the Lawrence Berkeley National Laboratory) and the Soviet Union (at the Joint Institute for Nuclear Research). The US team of Albert Ghiorso, Torbjørn Sikkeland, Almon Larsh and Robert Latimer had a strong claim to making element 103 in 1961 when they bombarded californium atoms with boron nuclei. This was of course scrutinised by the Soviets at JINR, and some of their criticisms held ground at the time. Regardless the Berkeley team put forwards their suggested name as lawrencium, after the physicist Ernest Lawrence.

JINR themselves made their first claim to element 103 in 1965. They had bombarded americium with oxygen atoms to try and create the heavy element, and although they could not repeat certain confirmation experiments they were confident that they had created element 103 and put forward the name rutherfordium after Ernest Rutherford.

The battle of the Ernests continued for years with each side claiming to have created various isoforms of element 103. This battle did not conclude until 1971, when the US scientists measured the decay properties of their element 103 isotopes. These experiments confirmed not only their own attempts at creating element 103, but a whole load of JINR attempts too. Despite this IUPAC gave the credit to the US team, and lawrencium as a name stuck. The contribution of the Soviet team in the discovery though was acknowledged in 1992 by IUPAC labelling them as co-discoverers of lawrencium. For anyone worried about Ernest Rutherford’s legacy, see my post on rutherfordium and you will be relieved.

So why would Ernest Lawrence earn himself an element name? Well not only did he found the Lawrence Berkeley National Laboratory and the Lawrence Livermore National Laboratory in California where a lot of subsequent elements were discovered, but his Novel-Prizeworthy design and use of the cyclotron was essential in the discovery of heavy elements like plutonium. Although it must be noted that the first invention of the cyclotron goes to Leo Szilard of Hungary, Lawrence developed and patented the first cyclotron in the United States. The cyclotron works by accelerating particles- that is, it uses a strong magnetic field to shoot charged particles like protons and atoms’ nuclei out in a concentrated beam. Particle accelerators like the cyclotron are what are usually doing the “bombarding” that I have been talking about when superheavy elements are being created, and also play a role in creating radioisotopes required forimaging in nuclear medicine. So, although more modern particle accelerators eventually superseded the cyclotron such as the synchotron in the 1950s, without Lawrence’s machine in 1932 so much nuclear physics and medicine wouldn’t be possible today.

The fancy new cyclotron at the Lawrence Radiation Laboratory in Berkeley in 1939. Stood around it are (left to right) Dr D Cooksey, Dr D Corson, Dr Ernest Lawrence, Dr R Thornton, Dr J Backus, WS Sainsbury, Dr LW Alvarez and Dr EM McMillan (from the American Institute of Physics through Wikimedia Commons).

And that’s lawrencium: without its namesake, it would not exist!