Clockwise from left: Swedish chemist Johan Gadolin, indirect namesake of gadolinium (from SnappyGoat); a brownish lump of gadolinium (from Wikimedia Commons); gadolinium as it appears in the periodic table.
Is it me or are quite a lot of rare earth metals coming in these posts at the moment? Here we have gadolinium, another quite malleable metal that can react with oxygen and water in atmospheric air to form an oxide or hydroxide coating over it.
Gadolinium was discovered in 1880 by Swiss chemist Jean Charles Galissard de Marignac in the minerals cerite and gadolinite (after which the element was named). After performing spectroscopic analysis on the minerals de Marignac found that combinations of wavelengths of light not seen before were being given off, suggesting that there was a new element within. The mineral gadolinite was named after Finnish mineralogist and chemist Johan Gadolin, who was the first to isolate a rare-earth element oxide, yttrium. Extra fun fact- the surname Gadolin comes from the Hebrew gadol, meaning “great”, and this is to date the only element with etymology rooted in Hebrew.
Gadolinite- a mineral containing, amongst other things, gadolinium oxide. From Wikimedia Commons.
The uses for gadolinium are quite small, but still important in their areas! Gadolinium is a very useful metal in metallurgy, as adding as little as 1% to chromium and iron alloys can vastly improve their workability and resistance against higher temperatures and rusting. Gadolinium is also very good at absorbing neutrons, and therefore is often used in nuclear reactors to limit the amount of neutrons being released during reactions, which could get out of control! Compounds containing gadolinium can give off a green colour when excited with energy, often resulting in their use as in old colour televisions.
One of gadolinium’s most useful properties though is that it is paramagnetic (susceptible to magnetic fields and will align with them, becoming magnetic themselves whilst the field is there) at room temperature. I talk a bit more about magnetism in my iron post. This magnetic property means that very small amounts of gadolinium in nanotubes (called gadonanotubes) can be injected into the body, where they accumulate in abnormal tissues in the body, for example where tumours are. The paramagnetism of the gadonanotubes means that these accumulations can be detected using magnetic resonance imaging (MRI), which detects these molecules by quickly altering the magnetic field around the body and measuring atom nuclei that spin as a result. This can build up an image of the body, and where those gadonanotubes have accumulated can diagnose tumours and other strange growths. Extra fun fact here too- MRI used to be called NMRI (nuclear magnetic resonance imaging) because of the fact it is the nucleus of the atom which spins. But it was thought that the word “nuclear” has bad connotations and so people would be more spooked if it was in a medical term. In research, where it is not used on humans, it is often still called NMR.
Gadolinium’s paramagnetic properties have led to uses as markers for tumours in MRI scans. From Wikimedia Commons.
Another fun use of gadolinium’s magnetism is in magnetic refrigeration. Magnetic refrigeration uses what is known as the magnetocaloric effect, whereby certain substances exposed to a changing magnetic field change in temperature. Gadolinium and alloys containing gadolinium increase in temperature when in a magnetic field, and a drop in temperature when taken out again. There is evidence that using a permanent magnet, some powdered gadolinium and some clever water circulation can be used to make a fridge that doesn’t require massive amounts of energy or atmosphere-destroying CFCs. Basically the magnetic field would be applied to the gadolinium, it would heat up, and a stream of water would carry that thermal energy away. Then the magnet would be taken away from the gadolinium, which would cool down, and then a different stream of water moving past would be cooled, and then sent around the fridge to cool the insides. Pretty nifty, but it is still a work in progress so no magnet fridges on the market just yet!
The complex workings of a magnetic refrigerator. The water coming from the magnetocaloric material (gadolinium) touching the magnet (top) is coming out hot, and the water coming from the gadolinium not touching the magnet (bottom) is coming out cold. From YouTube (https://www.youtube.com/watch?v=KrQR8h4NKk0&ab_channel=HKMVision3Sixty).
And that’s gadolinium- the Hebrew, magnetic and great element!
Clockwise from left: lanthanum is used in the carbon lighting for cinema projectors (from Wikimedia Commons), a small lump of lanthanum (from Wikimedia Commons), lanthanum as it appears in the periodic table.
Today we have the element that lends its name to the lanthanide series-lanthanum. The lanthanide series are 14 elements with similar properties that sit above the actinide row in the periodic table. They are also, along with scandium and yttrium, named “rare earth metals”, although this is a bit of a misnomer as they are pretty abundant in the Earth’s crust, but are often found together in ores. Anyway, just like the subsequent lanthanide series, lanthanum is a silvery soft metal that tarnishes very quickly in atmospheric air.
Based on previous posts, it may not surprise any of you to learn that lanthanum was a) discovered in the 19th century and b) discovered by a Swede. From a Swedish mine the mineral cerite was found, from which a substance called ceria was isolated by Vilhelm Hisinger and Jöns Jacob Berzelius. Carl Gustaf Mosander then took a look at ceria in 1839, and found that it was a mixture of various elemental oxides. Whilst analysing some cerium oxide Mosander found that some of it was soluble (not a property of cerium oxide), and determined that the soluble substance was a new element’s oxide. Mosander then named it “lanthanum”, using the Greek lanthanein (λανθάνειν) which means “to lie hidden”. Strangely Mosander did not reveal this discovery immediately, waiting instead to reveal that he had extracted another element from cerium that he named didymium (which turned out to be a mixture of praseodymium and neodymium). This gave a student called Axel Erdmann the chance to independently discover lanthanum from a mineral deposit in a Norwegian fjord.
A lot of elements ended up coming from cerite. From Wikimedia Commons.
We have covered a lot of the uses for lanthanum through other posts. For example, lanthanum oxide was mixed with zirconium oxide in the earliest gas mantles, meshes of metal oxides that shone brightly when heated by a flame. These mantles shone with a strange green light and were quickly replaced by better mantles. An alloy of lanthanum with new earth metals like cerium and neodymium is called mischmetal. Mischmetal is pyrophoric, it can easily ignite at lower temperatures, and therefore is often used in lighters as the ignition “flint”. Lanthanum alloyed with nickel can make hydrogen “sponges” which can reversibly bind hydrogen in very high amounts, and are used to store hydrogen in hydrogen-powered vehicles.
Lanthanum and rare earth metals are a key feature of mischmetal, which in turn are essential for lighters. From Pixnio.
Another use for rare earth metals in combination with lanthanide is in carbon arc lamps. These are lamps where two carbon rods with electricity running through them touch together to complete a circuit. The rods are then gently drawn apart, which creates a line of electrical energy between the two rods called an “arc”. This arc heats the two rods, and the carbon on the tips are vaporised, creating a lot of light. Lanthanide mixtures with lanthanum in these arc lamps increase the luminosity even further, and ensure that the spectrum of light given off is close to that of sunlight. These carbon arc lamps were used in cinema projection and studio lighting. Another thing lanthanum, or more accurately lanthanum (III) oxide, can do is alter the refractive index (the speed of light passing through a substance) of glass. This has lead to lanthanum glass being used in specialised glasses, cameras and telescopic lenses.
Lanthanum and rare earth metals have use in fancy camera lenses. From Avalon Advanced Materials
And that’s lanthanum- a projecting, hidden and “rare” element!
Clockwise from left: a lump of lithium submerged in oil (from Wikimedia Commons), rechargeable lithium ion batteries are one of the most common in laptops and mobile phones (from Wikimedia Commons), lithium as it appears in the periodic table.
Another very light element with lithium today. In fact, lithium is the lightest element that is solid at room temperature, as the only lighter elements are the gases hydrogen and helium. Lithium is also the lightest of what are called the alkali metals: elements in the first group (column) of the periodic table that includes sodium and potassium. These elements have only one electron in their outermost shell- this means they react really easily with other substances to donate that electron to another element that only needs one more electron to fill their outermost shell. This is why these alkali metals are stored in oil- they react so strongly with water that even if they are just exposed to water vapour in the air, they form a thick layer of that metal’s hydroxide (e.g. lithium hydroxide). These hydroxides are alkalis, hence the name alkali metal. If you want to have some fun, look up videos of these elements reacting in water, it is usually pretty intense!
The atom structures of some alkali metals: lithium (top left), sodium (top right), potassium (bottom left) and rubidium (bottom right). You can see that the outer electron of each structure is on its own, just waiting to react with another atom! Adapted from Wikimedia Commons.
The discovery of lithium comes in the late 18th-early 19th century in a great country for finding new elements: Sweden. Brazilian naturalist José Bonifácio de Andrada found a mineral in a mine on Utö island in Sweden which he named petalite. Petalite can be a variety of different colours, but it was noted that burning the mineral gave a distinct and intense crimson flame. In 1817 Swedish chemist Johan August Arfwedson found when analysing petalite that it contained a new element, which reacted and formed compounds similarly to sodium and potassium. Arfwedson and his boss Jöns Jakob Berzelius went with the name lithium, using the Greek lithos (λιθoς), which meant “stone”, as the element was found in a solid mineral, whereas sodium was known to exist in animal blood, and potassium was found in the ashes of plants (potash).
The mineral petalite, the first lithium compound found in nature. It can come in a variety of colours depending on what’s in it, and is often used as a gemstone. From Wikimedia Commons.
Possibly one of the biggest modern uses for lithium is in lithium-ion batteries. These are the rechargeable batteries you will find in most laptops, mobile phones, tablets and handheld games consoles. Lithium’s eagerness to donate that electron from its outer shell combined with how small the atom is means that you can get a high energy density- that is, a larger amount of electrons to donate into the circuit in a small space. The way a lithium ion battery works is that there are two chambers- a cathode and an anode- where the cathode contains a lithium containing compound like lithium cobalt oxide, and the anode contains another conductive chemical like graphite. When your battery is flat, all the lithium atoms are in the cathode, but once you plug a charger in, the charge difference created by the power input pulls the electrons out of the lithium in the cathode, round a circuit, and into the graphite at the anode. The now positively charged lithium ions can pass through a special membrane between cathode and anode to reunite with the electrons amongst the graphite. Once all the lithium ions and electrons are at the anode, the device is fully charged. While you are using your phone/laptop/Nintendo DS, the electrons are passing back through the circuit from anode to cathode, powering the device. This also causes the lithium ions to start passing back through their membrane to the cathode to reunited with the electrons again. This reversible movement of lithium ions and electrons through two separate paths is what makes the battery rechargeable.
My attempt at drawing a lithium-ion battery. When the battery is charging (top), the electrons (yellow) are moving around the external circuit (bronze lines) from anode to cathode, with the lithium ions (green) moving across their specialised membrane to greet them. When the device is being used, electrons pass back from the cathode to the anode whilst powering the device. The lithium ions move back with them across that membrane. The red dots are the anodic material (often lithium cobalt oxide) and the hexagons are graphite at the cathode.
Lithium can be alloyed with other metals like aluminium, copper or magnesium to make them stronger and lighter. These alloys can be used for armour plating, bike frames, fast trains (because they need to be lighter) and the classic in these blog posts: aircraft.
Lithium compounds also have a lot of interesting uses. As lithium burns bright red, flares and fireworks often use lithium chemicals to add a red colour. Compounds like lithium carbonate and lithium oxide do not fluctuate in size a lot when heated, meaning they are often used to glaze oven ceramics like casserole dishes. Lithium chemicals where the lithium has bonded to a halogen (like chlorine or bromine) are hygroscopic, which means they very readily bind to water. This is often used to dry atmospheres in industry, as well as in air conditioning to dehumidify. The positively charged lithium ion as a part of salts has also been shown to help in the treatment of mental health issues such as bipolar disorder, schizoaffective disorder and manic depression. It is not entirely clear why lithium has this effect though, and one must be careful because if the dosage is too high lithium can be toxic!
Oven-bound dishes are often glazed with lithium oxides as they do not change size too much when heated. From PxHere.
And that’s lithium- the water-loving, rechargeable, tiny solid element!
Clockwise from left: a big lump of sulphur (from Wikimedia Commons), sulphur as it appears in the periodic table, sulphur is behind what keeps your hair strong (from Pixabay).
I’m actually a little behind the times with the old British way of spelling sulfur with a “ph”. The official spelling of the yellow element was accepted to be “sulfur” by IUPAC (the International Union of Pure and Applied Chemistry) and the Royal Society of Chemistry in the late 20th century, even though before that was the US spelling of the word. An alternative term for sulfur was brimstone (meaning “burning stone” in Old English), as burning sulfur creates the incredibly pungent eggy sulfur dioxide (SO2). But we’ll get back to sulfur’s smelly compounds later.
The word sulfur comes from the Latin “sulpur“, and has been known about for millenia. Sulfur is mentioned in the Torah, Ancient Egyptian medical papyrus (where it was used to treat inflamed eyelids) and in the Odyssey (Ancient Greeks used it for fumigation). In Ancient China, sulfur was used both in traditional medicine and (when it was clear that sulfur was flammable) to make black gunpowder. Alchemists subsequently picked up on the strange flammable element, using it in reactions with metals and putting it forward as a cure for certain ailments like ringworm, acne and scabies. There might have been something in some of these treatments, as the sulfur would have slowly reacted with the air to form sulphurous acid, which does have some antimicrobial effects.
Sulfur is one of the active components of gunpowder. From Wikimedia Commons.
The identification of sulfur as an element did not come until the early 19th century. French chemists Louis-Josef Gay-Lussac and Louis-Jacques Thénard were the ones to prove this, despite the famous element-discoverer Humphry Davy being convinced that it was just a hydrogen-containing chemical.
So what do we use sulfur for now? Well a use that we have covered in the past is rubber vulcanisation. Rubber is a collection of polymers- long strands of the same chemical bonded together in a line. Vulcanisation heats these polymers with sulfur, which forms cross-links between the strands to make them even more rigid and durable than before. Vulcanised rubber can then be used to make hoses, shoe soles, car tyres, bouncy balls, erasers and even mouthpieces on musical instruments!
Garden hoses are just one of the uses of vulcanised rubber! From Pixabay.
Sulfur compounds are where things get really interesting, and quite stinky. A group of sulfur-containing chemicals called mercaptans are particularly smelly, and as well as use in silver polish, pesticides and fertilisers, are famous for being the substance we add to natural gas to give it a noticeable smell. So detecting gas leaks in your home is all thanks to sulfur! Sulphuric acid, one of the more famous acids, is a major export in the Western world. H2SO4 is used an awful lot in the chemical industry in production of other compounds, and is also used in wastewater treatment, extracting phosphate and minerals and oil refining. Calcium sulfate, also known as gypsum, is used as a plaster, mortar and in cement in construction. Gypsum has historically also been used for sculptures in the form of alabaster. So sulfur has great use both on its own and in various compounds!
Alabaster made from gypsum (calcium sufate) has frequent use in sculpture. From Wikimedia Commons.
Once again though we must finish on the importance of sulfur in life. Sulfur is the 5th most abundant element on Earth, and is essential to all living organisms. Organosulfur compounds (carbon-based chemicals with sulfur atoms in them) are what are behind smelly substances such as garlic and skunk scent, as well as antibiotics like penicillin, . We humans have on average 140g of sulfur in our bodies, a majority of which is in our proteins. Proteins are made up of building blocks called amino acids, some of which contain sulfur atoms. One particular amino acid, called cysteine, can create cross-links with other cysteines either within the protein or with other proteins through bonding their sulfur atoms together. These are called disulfide bridges, and are some of the strongest bonds that can happen between proteins. Disulphide bridges help keep maintain a protein’s structure robust, a bit like with the vulcanised rubber. One of the most well known uses of disulphide bridges is in a group of proteins called keratins, which make up hairs, feathers and nails. The extensive cross-linking that disulfide bridges provide allow these structures to stay strong and insoluble, and explains the awful smell that occurs should you accidentally set fire to your hair. This also explains the classic “rotten egg” smell- eggs contain a lot of sulfur for the future chicken’s feathers, and when an egg goes off that sulfur becomes incredibly smelly hydrogen sulfide.
A stupid pun I made once, where I connected God and Adam’s fingers with a disulphide bridge and named it the “cystine chapel” (cystine is the name of two cysteines joined together). It got some likes on Reddit.
And that’s sulfur- a flammable, stinky and cross-linking element!
Clockwise from left: some incredibly cold (under -252.87°C) liquid hydrogen (from Wikimedia Commons), the Hindenburg zeppelin was infamously full of flammable hydrogen gas (from Picryl), hydrogen as it appears on the periodic table.
It is strange that it took 104 posts to get to the smallest and lightest element in the periodic table, but hey these were randomly selected. Hydrogen is not only the most abundant element in existence, but also the most abundant chemical in the Universe too, making up around 3/4 of all baryonic matter (anything made of protons and neutrons, like atomic nuclei)!
Hydrogen is also fundamental when it comes to understanding how acids and bases work. Effectively a measure of how acidic a substance is is related to the concentration of positive hydrogen ions present when the substance is dissolved in solution (usually water). The higher the concentration of hydrogen ions, the higher the acidity, with a higher concentration of hydrogen ions than standard water being labelled an acid, and a lower concentration of hydrogen ions than water being labelled a base (also called an alkali if dissolvable in water). This is actually what pH is measuring- pH stands for power of hydrogen (or potential of hydrogen, we’re not too sure), and is an inverse measurement of the magnitude of hydrogen ion concentration. The lower the pH, the higher concentration of hydrogen ions, the more acidic. The reaction between a base (pH above 7) and an acid (pH below 7) usually involves the exchange of the hydrogen ion from the acid to the base. So hydrogen ion concentration is responsible for pretty much any acid or base you can think of: vinegar (pH=2.5), bleach (pH=12), stomach acid (pH=1.5-3.5), coke (pH=2.3), the list goes on!
The concentration of hydrogen ions in a solution (pH, left side numbers) gives an idea of how acidic a substance is. From Wikimedia Commons.
Biologically hydrogen is also incredibly important. Just like carbon, hydrogen is used in pretty much every biological macromolecule, including nucleic acids like DNA and RNA, proteins, carbohydrates like sugars and fats. It is also, along with oxygen, what comprises water (H2O), a fundamental chemical in life. The concentration of hydrogen ions in different compartments of the cell is also really fundamental. If there is a pH gradient across a biological membrane (for example between the outside and inside of a cell), then hydrogen ions will want to move across the membrane so that the pH is level on both sides. This need to move across the membrane is called the proton motive force (because largely speaking positive hydrogen ions are just protons), and is deliberately created across membranes in the mitochondrion using the breakdown of sugars and other molecules a to generate energy for the cell through respiration (see the oxygen post). Chloroplasts in plants also use light energy to create a proton motive force across internal membranes to drive the generation of chemical energy through photosynthesis. So hydrogen ions moving across membranes is fundamental to all life!
My quick diagram on how the proton motive force can be used to generate energy for the cell. A series of proteins (red) use energy from either molecule breakdown (respiration) or light (photosynthesis) to pump hydrogen ions across a lipid membrane (lilac circles and lines). This high concentration of hydrogen ions really wants to pass back across the membrane to the lower concentration region, so must do so through a special protein (orange) that, like a water wheel, uses the flow of protons to generate energy for us.
But enough biology from me, let’s talk about how hydrogen was discovered. Despite its abundance, hydrogen as an element was not discovered until 1671, when Irish chemist Robert Boyle found a strange gas being released when iron filings were mixed with acids. Almost a century later, English chemist Henry Cavendish took this experiment further, and named the gas “inflammable air” in 1766, potentially connecting it to the theoretical substance phlogiston, thought to be the flammable component of things. He then found 15 years later that burning this gas created water. The naming of hydrogen falls to French chemist Antoine Lavoisier, who repeated Cavendish’s experiments in 1783. He used the greek hydro (ὑδρο) which means “water”, and genes (γενής) meaning producer. So effectively hydrogen means “water producer”.
After that homemade scientific image I felt bad, so here is some nice water. From Wikimedia Commons.
Hydrogen has some more artificial uses, which is unsurprising considering its abundance. As it is a lighter gas than air and even helium, hydrogen was originally used in floating balloons and zeppelins. However, after the Hindenburg disaster, in which a zeppelin containing a huge balloon of hydrogen ignited, exploding and crashing and killing 36 people, hydrogen wasn’t used as much for these purposes. Hydrogen gas mixed with nitrogen is also used during flat glass production to prevent oxygen reacting with the glass as it is cooling. Hydrogen being the smallest element is gaining increasing use as a flushing gas, cleaning out and removing oxygen from tiny gaps in electronics like silicon chips.
The addition of hydrogen to a chemical involves a reaction called hydrogenation. This reaction useful in many chemical industries (for example hydrogenating nitrogen to make ammonia), but also in food production. Adding hydrogen to fatty acids and lipids helps create regularly structured chains of carbon and hydrogen, which can pack together more easily and therefore create fats that have a higher melting temperature. In fact, fats where no more hydrogens can be added are called saturated fats, and hydrogenation can help create artificial saturated fats like margarine. Unsaturated fats, which have less regularly structure carbon-hydrogen chains and are more likely a liquid at room temperature include olive and sunflower oil.
Margarine is an artificially hydrogenated fat that can be quite bad for you in excess! From Open Food Facts.
Recently, hydrogen has also been sought out as a source of fuel. The release of energy usually comes from the reacting of hydrogen with oxygen to make water, either through direct combustion of hydrogen or in a battery where the redox reaction can occur (hydrogen fuel cell). The process itself is a zero-emission system, as it only uses hydrogen and oxygen to make water, but the acquisition of hydrogen gas is quite difficult to achieve as extracting it from fossil fuels is unsustainable and there aren’t abundant natural sources of hydrogen on Earth. So the technology exists to use hydrogen as a fuel, and is used in spacecraft, buses and cars, but finding a sustainable source of hydrogen that doesn’t take more energy than it gives out requires further work. There are lines of research looking at using solar energy or even organisms that produce hydrogen gas as a by-product of metabolism (including the green algae I worked on for my PhD, Chlamydomonas reinhardtii) as a source, so there’s hope!
Chlamydomonas reinhardtii, potential hydrogen gas source. Any excuse to get my favourite single-celled green algae into things! From protist.i.hosei.ac.jp.
And that’s hydrogen- the smallest, acidic and FLAMMABLE element!
Clockwise from left: some shards of vanadium (from Wikimedia Commons), vanadium as it appears on the periodic table, piston rods often use vanadium steel due to its toughness (from Pikist).
I always like to find the most tenuous connections between element etymology, so for vanadium I will say that in a way it was named after the same Goddess as Friday. Bit of a stretch when you see how below but I’m sticking by it!
Vanadium is a transition metal, so once again we can expect some colourful oxidation states. The oxidation states that vanadium most commonly achieve (and their colours) are +2 (purple), +3 (green), +4 (blue) and +5 (yellow). This means vanadium is very happy to lose either 2, 3, 4 or 5 electrons from its atoms, and the electron configurations given in these ions result in the absorption of specific wavelengths on the visible spectrum, giving nice bright colours!
The oxidation states of vanadium have excellent colouring. From left to right the oxidation states are +2 (purple), +3 (green), +4 (blue) and +5 (yellow). From Steffen Kristensen.
Vanadium was an element that was discovered twice. The first time was at the start of the 19th century when Spanish mineralogist Andrés Manuel del Río extracted the element in Mexico from what is now called vanadinite, but was then called “brown lead“. Del Rio initially named the element panchromium because of all the colours that the element’s salts could form (pan=”all”, chroma=”colour”), and later erythronium (from the Greek erythro, meaning “red”) because these salts turned red when heated up. Unfortunately when French chemist Hippolyte Victor Collet-Descotils analysed a sample he convinced Del Rio that it was chromium with impurities, and so Del Rio retracted his claim.
Vanadinite: just some contaminated chromium ore? From Wikimedia Commons.
This false retraction meant that vanadium stayed a secret for 30 more years, after which Swedish chemist Nils Gabriel Sefström found vanadium in some iron ores in Stockholm. Sefström decided to go with vanadium for the element’s named after the Norse Goddess of beauty, love and fertility Vanadís, who also goes by the name Freyja (which is where we get Friday from). Apparently this choice was because Sefström noticed there wasn’t an element beginning with the letter “V”, which is a little strange but fair enough. German Chemist Friedrich Wöhler also confirmed del Río’s findings in 1831, so Andrés did get some closure on his work even if his element names did not go through in the end.
The Goddess Vanadís (also called Freyja), namesake of vanadium. “Freyja and the Necklace” by James Doyle Penrose, found through norse-mythology.org.
Vanadium’s colourful oxidation states can sometimes be used in coloured ceramics and glass, but the main use of vanadium metal is in alloying with iron and steel. Vanadium steel is very strong, and shock and vibration resistant, meaning it is often used in axles, piston rods, crankshafts and armour plating. Vanadium steel with increased carbon also gets use in surgical instruments and various tools for its incredible robustness. Also combining vanadium with titanium and aluminium provides a very tough heat-resistant alloy used in jet engines.
Crankshafts, which convert reciprocating (back and forth) motion into rotational motion, often use vanadium steel to resist vibrations and maintain strength. From Wikimedia Commons.
Vanadium has also been found to be used in various enzymes, and seems to be very important to sea life. Many marine algae have an enzyme called vanadium bromoperoxidase, an enzyme that helps remove dangerous levels of hydrogen peroxide that can be produced during photosynthesis. Strange little sea invertebrates called ascidians and tunicates actually store vanadium in specialised blood cells called vanadocytes, although the current reason for this is unknown. Some experts have suggested that it is used to deter predators. Some soil-based bacteria also use vanadium in nitrogenases- enzymes that “fix nitrogen“, which means they convert atmospheric nitrogen into nitrogen chemicals usable by nature, like ammonia. Vanadium may even be essential in human diets, but this has not been 100% confirmed yet.
Ascidians like to accumulate vanadium in their blood, for some reason… From Wikimedia Commons.
And that’s vanadium- the colourful, lovely and saline element!
Clockwise from left: a gleaming lump of molybdenum (from Wikimedia Commons), human teeth enamel is found in teeth enamel and is thought to help prevent decay (from Wikimedia Commons), molybdenum as it appears in the periodic table.
I don’t think we’ve had an element straight up named after another element yet have we? Protactinium has actinium in there, but molybdenum’s name comes purely from the fact that people got it mixed up with another element- lead (the Ancient Greek for lead was “molybdos“). It is also an excellent element to speak aloud, gives your mouth a real workout. Molybdenum.
Molybdenum’s ore (molybdenite) was not only confused often with lead ore (also known as galena). It was also confused with graphite (carbon), which completes a triangle as it was originally thought that graphite was a form of lead. Very confusing indeed. Our Swedish friend Carl Scheele was the one to first state molybdenum as a new element, after fellow Swede Bengt Qvist deduced that molybdenite did not contain any lead, both in the 18th century. Scheele suggested molybdenum using the mineral as a template, hence the confusing lead association. Once other fellow Swedish chemist Peter Hjelm managed to isolate elemental molybdenum from the ore in 1781, the new element was confirmed.
I guess you could sort of get molybdenite (left) confused with galena (right). Both from Wikimedia Commons.
It’s going to come as no surprise to people who’ve read a few of these posts when I say that this metal element has uses as a part of alloys. Adding molybdenum to steel increases its robustness against corrosion, hardness and electrical conductivity. Molybdenum also has a very high melting temperature, thus leading to this “moly steel” being used a lot in engines, aircraft, military armour and light bulb filaments. Molybdenum also appears in tools like drills and saw blades.
The high temperature resistance and hardiness of molybdenum alloys lends well to big tools with moving bits. From Wikimedia Commons.
Molybdenum also plays an essential role in biology. Being a transition metal, molybdenum has a lot of what are called oxidation states- due to the arrangement of their electrons in their atoms, molybdenum can donate 1, 2 or even 4 electrons to other atoms. This versatility in moving electrons means molybdenum is great in redox reactions (a portmanteau of reduction and oxidation, which mean gaining and losing an electron respectively, effectively redox is the passing of an electron from one thing to another). Therefore molybdenum is used by a lot of enzymes in various organisms that need to move electrons from one chemical to another. These include nitrogenases (which reduce nitrogen gas to ammonia), xanthine oxidase (which play a role in creating purines, a precursor to nucleic acids like DNA) and sulphite oxidase (which oxidises sulphite into sulphate, whilst using that taken electron to provide energy for the cell through respiration). As the above photographs also suggest, molybdenum features in tooth enamel and is thought to be involved in protecting against decay! Being deficient in molybdenum can cause seizures, nausea, headaches and in extreme cases a coma! Thankfully molybdenum can be found in most foods directly from organisms (beans, beef, milk, nuts and vegetables) so you should be safe.
Don’t forget your beans everyone! From Pikist.
And that’s molybdenum- the euphonious, lead-like and enzymatic element!
Clockwise from left: a very round lump of tellurium (from Wikimedia Commons); the Earth, or Tellus as it is known in Latin (from Pixabay); tellurium as it appears on the periodic table.
Today’s element, tellurium, is an example of what’s called a metalloid. The metalloids are a bunch of elements that have a lot of properties similar to metals (they look shiny and silvery and can somewhat conduct electricity), but also a lot of properties similar to non-metals (they are brittle and have similar chemical reactivity to non-metals). A confusing set of elements, to the point where there is no specific definition of what a metalloid is. The most commonly prescribed metalloids are boron, silicon, germanium, arsenic, antimony and our friend tellurium.
Tellurium was first found in 1782 in what is now Romania but was then Transylvania (insert some joke about Dracula here). Austrian chief mine inspector Franz-Joseph Müller von Reichenstein found it in gold ore in a Transylvanian mine. At first it was thought to contain antimony, but the more Müller von Reichenstein tested it the more he found it to be something else that he could not identify. He ended up calling it aurum paradoxum (paradoxical gold) and metallum problematicum (problem metal), and did believe it to be a new element. Müller von Reichenstein sent a sample of the problem metal to German chemist Martin Klaproth, who had seen this new element before from a sample sent by Hungarian chemist Paul Kitaibel. Klaproth confirmed that this was a new element and named it tellurium from the latin Tellus, referring to the Earth.
Franz-Joseph Müller von Reichenstein, finder of tellurium. From worldofchemicals.com.
Although tellurium is too brittle to be used in construction on its own, the main use of the element nowadays is in metallurgy. Tellurium can add workability to iron, copper and steel, and improve the durability and resistance to sulphuric acid for lead. Tellurium in combination with cadmium and sometimes mercury makes a semiconducting material that has shown great efficiency in solar panels. Tellurium is also what is used in the “media layer” of rewritable discs like CD-R, DVD-R and rewritable Blu-Ray. This media layer uses a silver, indium, antimony and tellurium alloy that has a very specific microscopic crystal structure. When the disc has information written onto it, a laser heats certain bits of the alloy at a high temperature in a certain order, which liquefies that part of the alloy such that it loses its crystalline form. A computer can then detect which parts of the alloy have still got its crystal form and which bits don’t in order to read the information on the disc. This reaction is reversible however, whereby a lower temperature by a laser can return the alloy to its crystal form, allowing the disc to be written again.
Being able to write over your old CD mixtapes was made possible by tellurium! From Wikimedia Commons.
Tellurium has started being combined with other substances than metals too. Adding tellurium to glass increases its refraction, which is very useful in optical fibres (which I feel have been quite common lately), and is often used as a colouring agent for ceramics.
The final use of tellurium I wanted to mention is in vulcanising rubber. The word vulcanisation comes from the Roman God of fire and the forge Vulcan, and is a process that is used to harden rubber that involves (surprisingly enough) heating the rubber in the presence of a substance like sulphur or tellurium. This helps to form cross-links within the rubber that make it more hardy and heat/weather resistant. Tellurium vulcanisation can make rubber extremely heat resistant, a useful property for rubber items such as tyres.
Extra heat resistant rubber is useful in tyre making, although tellurium vulcanisation is still more expensive than just using sulphur. From Wikimedia Commons.
And that’s tellurium- the combining, hardening and earthly element! One final fact- breathing too much tellurium (for example if you work in an industry handling the element) can give you “tellurium breath”, which is apparently very garlicy!
Clockwise from left: a huge vat of liquid oxygen at the Cape Canaveral rocket launch site (from Wikimedia Commons); a diagram of the respiratory tract and lungs, whereby oxygen can get into our bloodstreams (from Pixabay); oxygen as it appears on the periodic table.
It’s the big 100! And what better way to celebrate the 100th element blog post than with the other big element of life (bar carbon)- oxygen. And oxygen is an interesting one, because as much as it provides us with life, in the wrong form it can be incredibly dangerous.
Oxygen has gone by many names throughout history, as thinkers through time are trying to figure out this invisible substance that we breath to survive. It was in the 2nd century BC where the first connection that we know of was made between combustion and the consumption of air. Philo of Byzantium, Greek engineer found that when he put an upside down container over a lit candle and surrounded the container with water that some water started slowly travelling up the container. Philo wrote this down in his book Pneumatica (using the Greek “pneuma” meaning “wind”), although he thought that some of the air in the container was being turned into fire and escaping through the glass. This experiment was repeated in the 17th century by chemist John Mayow, who also used a mouse instead of a candle to show that breathing also relied on this component of air, which Mayow named spiritus nitro-aerus (the spirit bit referring to how it allows for life).
My very basic drawing of Philo’s experiment. A lit candle in an upside-vessel is surrounded by water so that the air in the vessel is trapped (left). Over time, the oxygen in the air gets combusted by the flame, allowing the water to get sucked into the vessel (right). Philo wrongly thought that some of the air was turning into fire.
However, this spiritus nitro-aerus idea was quelled pretty quickly by a new idea called the phlogiston theory. German alchemist J. J Becher posited this idea in the 17th century, which stated that flammable substances were made up of two components: phlogiston (an entity released when the stuff was burned) and the dephlogisticated component, which was believed to be the “true form” of the original substance. For example, wood was just a combination of phlogiston and ash, the latter being the “true form” of wood. It all stemmed from the idea that as things burned, they got lighter. In terms of a flame going out after spending some time in a closed vessel (which nowadays we know is when the oxygen is used up), the idea there was that so much phlogiston had been released into the air that it was saturated, and therefore this “phlogisticated air” could not take any more phlogiston on and the reaction halted.
A wonderful visual depiction of the phlogiston theory and how it relates to phlogisticated air. From treetownchem.blogspot.com.
The very excellent if incorrect word phlogiston comes from the Greek word phlogistón meaning “burning up”. The phlogiston theory was further refined in the early 18th century by chemist Georg Ernst Stahl and one of his students Johan Pott, who even claimed that phlogiston was the basis of colours!
“But what about discovering oxygen?”, I hear you cry. Well that came later in the 18th century thanks to independent discoveries from Swede Carl Scheele in 1771, Englishman Joseph Priestley in 1774 and Antoine Lavoisier also in 1774. Scheel and Priestley generated oxygen through heating mercuric oxide, although Scheele called it “fire air” due to its combustibility and Priestley called it “dephlogisticated air” in line with the theory of the time. Lavoisier was the one to actively disprove the phlogiston theory and name oxygen as a new element. He figured this after heating tin and air in a sealed container and finding that the weight of the container not change, and that air rushed in when he opened the container as if air had been “used up” inside. This combined with his observation that the increase in weight of the heated tin was proportionate to the amount of air lost led him to conclude that something from the air was combining with the tin to make a new substance on its surface (now known to be tin oxide). He concluded that air had two parts: “vital air”, which was this combustible, breathable gas, and azote (“lifeless”) which was lifeless air. Vital air was changed by Lavoisier to oxygène (from Greek “oxy” meaning sharp in taste, like an acid, with “gen” meaning to produce) as further experimentation showed that this element was key in many acids. So yeah, oxygen literally means “produces acid”.
Battle of the chemists: Carl Scheele (left; from Store Norske Leksikon), Joseph Priestley (centre; from Wikimedia Commons) and Antoine Lavoisier (right, from Wikimedia Commons) all have claim to discovering oxygen.
So before we get onto the biological importance of oxygen, is there anything else we use oxygen for? Well apart from the chemical industry where oxygen-containing compounds like nitric acid, hydrogen peroxide, polyester, epoxyethene (antifreeze) and vinyl chloride, oxygen has an important use in the steel industry. Injecting oxygen into molten iron helps to remove impurities like sulphur and remove excess carbon by reacting with them to make sulphur and carbon dioxide respectively. This creates a purer, more effective steel.
Smelting iron to make steel requires oxygen to remove impurities. From PxHere.
So oxygen is an essential element to life, and this is typified by two molecules: water and diatomic oxygen. Water is two hydrogens bound to an oxygen atom (see all those internet experiments with “dihydrogen monoxide” for a fun demonstration of the demonisation of chemicals), and I don’t think I need to explain the importance of water, as the make up of our blood and cellular fluid. Diatomic oxygen- two oxygen atoms bonded together- is what is found in air. This is the oxygen that we breathe, passes from our lungs into our blood bound to haemoglobin in red blood cells, and passed around our bodies to where it can help us survive. But have you ever stopped and asked “why is oxygen so important?” If you have I will tell you.
Many people believe respiration is the act of breathing air, and yes that is one definition. But in biochemistry, respiration is an incredibly important and complex reaction whereby biological molecules like fats and sugars are broken down, and with the help of oxygen provide us with energy to perform all the important tasks in our cells. The respiration reaction all takes place in our cells, but the final part takes place in a very special structure within the cell called the mitochondrion (plural mitochondria). The mitochondrion has two sets of membranes, one inside the other, creating two spaces: the inner matrix, and the intermembrane space. When those fats and sugars are broken down, they donate electrons to a set of proteins that span the membrane separating the intermembrane space from the matrix. These electrons then get shuttled down a chain of these proteins until they reach an enzyme that uses those electrons to combine hydrogen ions and oxygen to make water. This whole process releases energy, which is used to pump hydrogen ions out of the matrix and into the intermembrane space. Now with so much concentrated hydrogen ions in this intermembrane space, all they want to do is get back into the matrix, and so they go through a turbine protein called ATP synthase. This energy of flowing hydrogen ions (like a water wheel) drive the ATP synthase to create ATP, a molecule you may remember from our phosphorus post as one of the main energy sources for the cell. ATP can help catalyse reactions, replicate DNA and allow the cells to divide and grow. The take home message from my long attempt to explain respiration is that without oxygen to accept those electrons in the mitochondrion, we would not be able to generate energy in our cells!
A nice and complex diagram of respiration, a process occurring in structures within the cell called the mitochondria, where oxygen (highlighted red) is used to provide energy for the cell in the form of ATP (highlighted in purple). Adapted from Wikimedia Commons.
Now if you’ve survived this very long article on oxygen thus far, I did promise the nastier side of oxygen, and it often occurs when this respiration reaction goes wrong. You see if an extra electron gets onto oxygen without the hydrogen ions joining it, you end up with reactive oxygen species. These highly reactive molecules can effectively react with and damage a bunch of things in your cells- proteins, membranes, even DNA! In fact, one of the hypotheses put forward about ageing is to do with reactive oxygenic species building up over time and attacking parts of your DNA that means they don’t replicate perfectly. This also occurs in photosynthesis, where energy absorbed from the sun is not used fast enough and so gets transferred to oxygen molecules, creating reactive oxygenic species that are dangerous to the chloroplast. So the fact that oxygen can accept electrons is both our source of energy and one of our greatest enemies!
It must be said there might be something in this old meme… From Meme Generator.net.
And thus concludes my slightly long-winded post on oxygen. I hope you’ve enjoyed this ride, and thank you all for joining me through the first 100 elements. Only 18 left to go!
Left: the state of Tennessee, namesake of the penultimate element. Right: tennessine as it appears in the periodic table.
Here we have the final element in group 17, and the penultimate element confirmed to date: tennessine (once again accompanied by that red underline showing the word hasn’t been around long). Along with californium, tennessine is named after a US state, and does not have an awful lot of uses outside the lab as the most stable isotope has a half-life of 112 milliseconds. That being said, this half-life is longer than scientists first predicted, adding evidence to what has been called the “island of stability”.
The island of stability is a theory that certain numbers of protons and neutrons in the atom’s nucleus (known as magic numbers) are much less inclined to be unstable and decay. This means that certain isotopes for elements, which will have these magic numbers of neutrons, will be more stable than first thought. This idea has had several elements that have shown to be more stable, with the magic numbers of protons or neutrons being 2, 8, 20, 28, 50, 82 and potentially 126. And if an isotope for an element happens to have both protons and neutrons with a magic number in them, well that makes for a super stable atom!
Oak Ridge National Laboratory in Tennessee, one of the collaborators in the creation of element 117. From research.tennessee.edu.
The creation of tennessine occurred in the 21st century as a result of a collaboration between the Joint Institute for Nuclear Research in Moscow and the Oak Ridge National Laboratory in Tennessee. The Lawrence Livermore National Laboratory also joined the collaboration a little later on. ORNL were for a while the only producer of berkelium as a by-product of californium production, which is why JINR wanted to work with them bombarding berkelium with calcium nuclei to try and create element 117. After overcoming some customs issues in Russia, berkelium was finally received by JINR in 2009 in lead boxes. They then completed the bombardment and reported a new element with atomic number 117 based on a new chain of decay of its atoms. The experiment was repeated in 2012, leading to the official recognised discovery of element 117 in 2015, only 5 years ago! And it was only 3 years ago when the name tennessine was established as the element’s true title, using the state of ORNL and key scientists in the collaboration and the classic halogen suffix “-ine”.
And that’s tennessium- the (more than expected) stable, cross-Atlantic incredibly modern element!
An Element A Day 