Uncategorized

The Periodic Table of Element Eytmologies


The seventh row of the periodic table is complete, resplendent with four new names for the elements 113, 115, 117 and 118. The International Union of Pure and Applied Chemistry (the organisation charged with naming the elements) has suggested these should be called nihonium (Nh); moscovium (Mc); tennessine (Ts) and oganesson (Og) and is expected to confirm the proposal in November.

Yuri Oganesyan.
Kremlin.ru, CC BY-SA

The three former elements are named after the regions where they were discovered (and Nihonium references Nihon the Japanese name for Japan). And “oganesson” is named after the Russian-American physicist Yuri Oganessian, who helped discover them.

After years of having to make do with temporary monikers while the elements were officially being added to the periodic table and evaluated by the IUPAC, these new names are much welcomed by scientists. Alas, those calling for names in tribute to great folk of popular culture have gone unheeded; Octarine (the colour of magic, according to Terry Pratchett), Ziggium (in tribute to David Bowie’s alter ego Ziggy Stardust) and Severium (in tribute to Alan Rickman and via Severus Snape) will not adorn the updated table.

Instead IUPAC have followed their rules which stipulate that “elements are named after a mythological concept or character (including an astronomical object); a mineral, or similar substance; a place or geographical region; a property of the element; or a scientist”.

But there wasn’t always such an organisation overseeing the names of the elements. Most of them have come about via contorted etymologies. So to give you an idea of the diversity of the most famous of scientific tables, I’ve turned it into an infographic and summarised a few of the eytmologies in numbers.

The Periodic Table of Elements’ Etymology.
Andy Bruning, Compound Interest, Author provided

Click here for a larger version.

Two of the elements stink. Bromine means “stench” and osmium means “smells”. France also appears twice on the periodic table in the form of francium and gallium (from Gaul) and its capital city, Paris, gets a mention (in the form of lutetium).

Three sanskit words – eka, dvi and tri, meaning one, two and three – were prefixed to elements and used as provisional names for those that had yet to be discovered. Eka- is used to denote an element directly below another in the table, dvi- is for an element two rows down and tri- is three rows beneath. Russian chemist Dimitri Mendeleev first used this nomenclature to fill in the gaps in his early periodic table, so element number 32 was known as eka-silicon until it was discovered and named germanium in 1886. Similarly, rhenium was known as dvi-manganese until 1926. Some 14 elements have had eka names including our four new additions which before their discovery were known as eka-thallium, eka-bismuth, eka-astitine and eka-radon.

Four of the elements are named after planets (Earth – in the form of tellurium, Mercury, Neptune and Uranus). A further two are named after dwarf plants (Pluto and Ceres), while one after a star (helium from the Greek for the sun – Helios) and another after an asteroid (Pallas) feature on the periodic table.

Five elements are named after other elements: molybdenium is from the Greek for lead, molybdos, while platinum comes from the Spanish platina meaning “little silver”. Radon is derived from radium, zirconium has its roots in the Arabic zarkûn meaning “gold-like” and nickle is from the German for “devil’s copper”.

Eight elements were first isolated from rocks quarried in a the small village of Ytterby in Sweden. Four of those elements are named in tribute to the village (ytterbium, erbium, terbium, yttrium).

15 are named after scientists, only two of whom were women: Marie Curie and Lise Meitner are immortalised in curium and meitnerium.

18 elements have had placeholder names derived from the Latin for the elements atomic number (for example ununoctium, now oganesson). This was introduced to stop scientists fighting over what their discoveries should be called. Nobody wants a repeat of the three-decade long “Transferium Wars” when battles raged between competing American and Russian laboratories over what to call elements 104, 105 and 106.

42 elements’ names are derived from Greek; 23 from Latin; 11 from English; five are Anglo-saxon; five German; five Swedish; two Norse; three Russian, and one apiece for Japanese, Sanskrit, Gaelic, Arabic and Spanish.

118 elements appear on the periodic table, and the seventh row is complete, but that doesn’t mean the table is finished. Laboratories around the world are busy smashing atoms together in an attempt to forge new even heavier elements. The hope is that before long these latter day alchemists will hit upon the fabled “island of stability”; a region of the table that harbours elements with half-lives much longer that the sub-second lives of nihonium, moscovium, tennessine, and oganesson.

Infographic for this article was made by Andy Brunning/Compound Interest

The Conversation

This article was originally published on The Conversation. Read the original article.

By June 11, 2016 4 comments Uncategorized

The chrome plated mystery of the Terracotta army’s swords



QIMG_6487in the 1st Emperor of China prepared well for the after-life. Throughout his reign he commissioned and built an eternal army of some 6000 soldiers, charioteers and cavalry. The  warriors stood in formation, buried at the foot of his tomb, there to guard the Emperor for eternity.

But all did not go as planned. Shortly after Qin was entombed chaos descended on his newly united China. Qin’s heirs, wishing to defeat him (even after his death) attacked his after-life defences. History tells that the underground barracks that housed the vast army of terracotta warriors were set alight. Fires smouldered for 90 days, structures around the ornate statues collapsed smashing the exquisite army. The broken soldiers and their bronze weaponry lay buried in ash and rubble. The great mausoleum was forgotten. Two millennia passed. Until in 1974, a peasant farmer, whilst digging a well, found fragments of a crushed warrior. And excavations began.

The thousands of individual Qin dynasty soldiers, have been painstakingly pieced together and placed back in formation. They are an awe inspiring sight. But I marvelled just as much when I saw no less incredible bronze weapons that armed the officers. Their swords are still sharp and largely unaffected by the 2200 years that have passed since they were forged. Instead of the green corrosion you’d expect on bronze artefacts the blades actually appear gun metal grey. Why this is the case is something of a mystery.
IMG_6489

IMG_6488

There are reports of an analysis of the artefacts conducted by the Chinese Research Institute of Nonferrous Metals and Chinese Academy of Geological Sciences (although I am unable to find the primary data). The suggestions is that a 10-15 micron coating containing chromium oxide (at up to 2% chromium) was found. The conclusion; for millennia this thin layer protected objects from the ravages of time and chemistry.

So where did the chromium oxide layer come from? Did the ancient Chinese metallurgists, as suggested by curators of the Terracotta army, really have chrome plating technologies thousands of years before it was developed in the west? Over the intervening time did the chromium shine lose its lustre as it slowly oxidised, resulting in the grey we see today? Is a 10 micron, dilute layer of chromium oxide really enough to impart anti-corrosion properties?  Or is there another explanation for the immaculate swords?

This isn’t the first time someone’s asked these questions. Its been discussed on a sword forum where suggestions include forgeries and serendipitous impurities in the alloy. The latter seems to be supported by Prof Frank Walsh, an electrochemist now at Southampton University, when he was interviewed for an ABC documentary back in 2003 where:

Professor Walsh notes that the heat from the fires and the presence of carbon would have provided a reducing environment in which chromium atoms could have migrated to the surface of the weapons. There they’d oxidise and form a protective coating … Metals do diffuse over time, so this ‘natural’ explanation is plausible.

For me this isn’t a totally satisfying explanation. Largely since it appears, from the items on display, that only the blade is free of corrosion. The hilt has clearly corroded. If the slow migration of chromium to the surface of the blade is responsible why didn’t this mechanism occur elsewhere on the swords? But the idea that Qin’s weapon smiths knew how to apply anti-corrosion layers to their creations seems rather fanciful.

Which leaves the above questions unanswered. So chemists, time to reopen discussions. What do you think is going on? Can anyone come up with a way that the ancient Chinese might have deliberately or accidentally protected the weapons?  Or what else might have resulted a corrosion free blade, whilst the rest of the weapon is tarnished?

P.S. Any Chinese chemists/metallurgists out there who might be able to track down the analysis of the blades?

By September 22, 2015 12 comments Uncategorized

Simulating C&EN and JACS

I decided to make a robot that would Tweet fake C&EN headlines and JACS titles. There are many ways one could go about doing this. The way I decided to do it is to use something called Markov chains. This is similar to how your cellphone’s keyboard works: Your cellphone will try to guess which word you want to type next based on your previous history of typing. I’ll give an example below.

Let’s say I have fed these two headlines into my database

  1. “Novel Ruthenium Catalyst”
  2. “Ruthenium Based MOFs”

The Markov chain will think headlines should start with either the word “Novel” or “Ruthenium”. Now let’s tell the bot to roll the dice and start constructing a sentence.

The bot picks: Ruthenium

The bot knows that after the word Ruthenium either “Catalyst” or “Based” are typical. Let’s have the bot roll the dice again.

The bot picks: Catalyst

Now the bot knows that the word “Catalyst” is associated with a full-stop and there is no way for it to generate anything further. So from only two headlines the bot is able to generate something unique, “Ruthenium Catalyst”. Based on these rules and the luck of the dice “Novel Ruthenium Based MOFs” would also be a possible headline for it to make.

I fed a large batch of real C&EN headlines into a database, told my bot to go at it, and Tweet what it comes up with, and also grab the first image on Google Images if someone were to search for that headline. Here is an example

C&EN Simulator

Sometimes I get lucky and the story is funny, usually it just comes out nonsensical, absurd, or worse an actual real headline. You can befriend the bot through this link: @C&EN Simulator

Taking it one step further I also made a JACS bot based on the article titles I have been scrapping at ChemFeeds for the past 7 years.

You can friend the bot here: @JACS Simulator

The bots will update randomly throughout the day. If you have any questions for me leave them in the comments. I can open source the code if there is any interest in such things.

Mitch

By September 11, 2015 1 comment Uncategorized

How science lost one of its greatest minds in the trenches of Gallipoli



August 10, 1915. The Gallipoli sun beats down on the back of a Turkish sharpshooter. He is patient and used to the discomfort. He wipes the sweat from his eyes and peers back down the sight of his rifle, sweeping back and forth across the enemy lines. He’s hoping to spot a target worth taking a shot at as each muzzle flash risks giving his position away.

His sight settles on the shoulder pip of a second lieutenant. The target bends down out of sight, then reappears, now with a phone at his ear. He stands still as he sends his dispatch. It’s an easy shot for the sniper. He squeezes the trigger and yet another young man dies.

Infantry from the British Royal Naval Division in training during the Battle of Gallipoli.
wikimedia

The Turkish soldier settles down in his hole, pleased with his marksmanship. He wonders if he’s made a significant difference to the war effort (probably not).

However, he may well have caused the single most costly death of the entire war. His victim, now lying in a trench on a peninsula in Turkey, is 27-year-old Henry Moseley. The loss to science is incalculable.

Hidden patterns

Despite his young age, Moseley had already made a stunning contribution to chemistry and physics. It is thanks to him that that the periodic table looks the way it does today.

He had graduated from Oxford just five years before his death. Immediately after graduating he was employed as a teaching assistant by the great physicist Ernest Rutherford in Manchester. Moseley hated it, describing his duties as “teaching elements to idiots” and his students as “mostly stupid”. His real passion was research, so in his spare time he used his energies to set up his experiments.

Moseley was working in an era of physics that was concerned with the power of X-rays. The Braggs, a father-son team working in Leeds, were developing X-ray crystallography. This allowed science to probe the atomic structure of molecules.

But instead of jumping on that bandwagon – shining X-rays at crystals to work out chemical structures – Moseley turned his attention to the elements themselves. He studied the X-rays the elements gave off when bombarded with electrons. His results had major implications for the famous periodic table in which elements are presented.

Back in 1869, Dimitri Mendeleev arranged the elements in a logical fashion. He ordered them by weight and then laid them out in a table. Next he shuffled the dimensions of his table to take similarities of elements into account. For example, lithium, sodium and potassium have similar chemical properties and were arranged in one group on a line of the table (modern tables have been flipped so that these groups are now in columns).

Mendeleev’s periodic system.
wikimedia

Likewise for fluorine, chlorine, bromine and iodine. And so the periodic table was born. The elements were now arranged in a clear sequence – and each was given an atomic number denoting its position in that sequence. But there were a few problems, some elements didn’t quite fit the order. Their behaviour suggested one position in the table, but their atomic weight put them somewhere else. So the atomic weight and atomic number of the elements didn’t quite correlate.

In Manchester, and later in Oxford, Moseley took samples of all known elements, from aluminium to gold, and measured the X-rays they gave off after bombarding them with electrons. He discovered that each element emitted a distinct frequency of X-rays, and that this frequency correlated with the atomic numbers. When he plotted the square root of the frequency, against the atomic number everything fell into straight lines on his graph.

For the first time it became clear that an element’s atomic number, corresponding to its position on the table, had a basis in physics and was not merely a convenient label. And that these numbers (confirmed by Moseley’s measurements) resolved the previous issues with the periodic table. He also noted points missing from his graph and surmised that these gaps must be due to yet-to-be discovered elements. It was wasn’t until 30 years after his death that that the last of Moseley’s missing elements were discovered.

Nobel effort

Moseley’s achieved all this in a research career lasting just 40 months. At the outbreak of war in 1914 he signed up, becoming a signalling officer in the Royal Engineers. Had he survived, it is likely he would have been awarded the 1916 Nobel Prize in Physics (as it was no Nobel Prize in Physics was awarded that year). There is no telling what other breakthroughs might have been achieved in the alternative history in which he survived the war.

There is one more legacy that Moseley left. His death raised the question of whether great minds such as his should really be risked on the battle field. Despite the war, the international scientific community was outraged at the loss of such a renowned scientist, who still had so much to offer.

From then on scientists were used in a very different way in wars. For better or worse scientists in the next great war developed penicillin, radar, programmable computers and, of course, the Manhattan project. All these inventions had much greater impacts on World War II than any of the individuals involved could have made at the front line.

The Conversation

Mark Lorch is Senior Lecturer in Biological Chemistry at University of Hull.

This article was originally published on The Conversation. Read the original article.

By August 10, 2015 2 comments Uncategorized