Transcript :
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You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.
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Chris Smith
Hello, this week supersonic steels, fast formula cars and upset Spanish scientists. But what are they arguing about? Here's Katherine Holt.
Katherine Holt
What's in a name? How do we decide what to call an element anyway? Is the name of an element the same in all languages? Does it matter? And who decides?
Well the answer to the last question is easy - the naming of elements is ultimately decided by IUPAC - the International Union for Pure and Applied Chemistry. The answer to the other questions is mainly 'it depends'! Take for example the case of element 74 - or as we call it in English - tungsten. Ever wonder why its symbol is W? Chemists in many European countries don't have to wonder why - because they call it Wolfram. The two-name confusion arises from early mineralogy. The name 'tungsten' is derived from the old Swedish name for 'heavy stone', a name given to a known tungsten-containing mineral. The name 'wolfram' comes from a different mineral, wolframite, which also has a high content of the element we call tungsten.
Until recently both names - tungsten and wolfram - were included in 'Nomenclature of Inorganic Chemistry - IUPAC Recommendations' or the 'Red book' as it is known in IUPAC circles. However in 2005 'wolfram' was dropped and tungsten became the sole official IUPAC name for this element. However, wolfram did not go down without a fight! In particular the Spanish chemists were unhappy to see the change - not least because their compatriots the Delhuyar brothers are credited with the discovery of the element and its isolation from the mineral wolframite. In their original paper, the Delhuyar brothers requested the name wolfram for the newly isolated element, saying 'We will call this new metal wolfram, taking its name from the matter of which it has been extracted.this name is more suitable than tungsten...... because wolframite is a mineral which was known long before...., at least among the mineralogists, and also because the name wolfram is accepted in almost all European languages....."
Although this may be a compelling case, IUPAC argues that is that its working language is English and so Tungsten is the most appropriate name. They make the point that students will have to learn some history of chemistry to know why the element symbol is W. The same is true also for a number of other elements, such as potassium, mercury, and silver whose symbols bear no relation to their English name.
However, it seems unlikely to me that such a colourful name as wolfram will be forgotten. In case you were wondering, it is believed to be derived from the German for 'wolf's foam'. Many centuries ago mid-European tin smelters observed that when a certain mineral was present in the tin ore, their yield of tin was much reduced. They called this mineral 'wolfs foam' because, they said, it devoured the tin much like a wolf would devour a sheep! Thus over time the name 'wolframite' evolved for this tungsten-containing ore.
In contrast to its semi-mythical role in early metallurgy, these days the applications of tungsten are highly technological, making use of its hardness, stability and high melting point. Current uses are as electrodes, heating elements and field emitters, and as filaments in light bulbs and cathode ray tubes. Tungsten is commonly used in heavy metal alloys such as high speed steel, from which cutting tools are manufactured. It is also used in the so-called 'superalloys' to form wear-resistant coatings. Its density makes it useful as ballast in aircraft and in Formula one cars and more controversially as supersonic shrapnel and armour piercing ammunition in missiles.
It seems to me that the name tungsten, or 'heavy stone', is justified by these applications, which exploit its strength and density. I'm glad, though, that the birth of chemistry in the activity of those ancient metallurgists and mineralogists is still celebrated by the use of the symbol W for element 74. This ensures that we never forget that there was a time, not so long ago, when many chemical processes could only be explained through metaphor.
Chris Smith
I always used to remember tungsten's letter W as standing for the wrong symbol, but can you think of the one letter of the alphabet that isn't used in the periodic table? Now there's something to ponder on. In the meantime, thank you very much to UCL's Katherine Holt.
Next week we'll meet the element that was introduced to the world in, its fair to say, a pretty unusual way.
Brian Clegg
The first hint the world had of the existence of Americium was not in a paper for a distinguished journal but on a children's radio quiz in 1945. Seaborg appeared as a guest on MBC's Quiz Kids show where one of the participants asked him if they produced any other new elements as well as plutonium and neptunium. As Seaborg was due to formally announce the discovery of Americium five days later he let slip its existence along with element 96.
Chris Smith
And Brian Clegg will be telling the story of the radio active element americium and how it keeps homes safe in next week's Chemistry in its element, I hope you can join us. I'm Chris Smith, thank you for listening and goodbye.
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Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists.com . There's more information and other episodes of Chemistry in its element on our website at chemistryworld.org/elements
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Tungsten metal was first isolated (1783) by the Spanish chemists and mineralogists Juan José and Fausto Elhuyar by charcoal reduction of the oxide (WO 3 ) derived from the mineral wolframite . Earlier (1781) the Swedish chemist Carl Wilhelm Scheele had discovered tungstic acid in a mineral now known as scheelite , and his countryman Torbern Bergman concluded that a new metal could be prepared from the acid . The names tungsten and wolfram have been used for the metal since its discovery, though everywhere Jön Jacob Berzelius ’s symbol W prevails. In British and American usage, tungsten is preferred; in Germany and a number of other European countries, wolfram is accepted.
The amount of tungsten in Earth’s crust is estimated to be 1.5 parts per million, or about 1.5 grams per ton of rock. China is the dominant producer of tungsten; in 2016 it produced over 80 percent of total tungsten mined, and it contained nearly two-thirds of the world’s reserves. Vietnam, Russia, Canada, and Bolivia produce most of the remainder. Tungsten does not occur as a free metal. It is about as abundant as tin or as molybdenum, which it resembles, and half as plentiful as uranium. Although tungsten occurs as tungstenite—tungsten disulfide, WS2—the most important ores in this case are the tungstates such as scheelite (calcium tungstate, CaWO4), stolzite (lead tungstate, PbWO4), and wolframite—a solid solution or a mixture or both of the isomorphous substances ferrous tungstate (FeWO4) and manganous tungstate (MnWO4).
For tungsten the ores are concentrated by magnetic and mechanical processes, and the concentrate is then fused with alkali. The crude melts are leached with water to give solutions of sodium tungstate, from which hydrous tungsten trioxide is precipitated upon acidification, and the oxide is then dried and reduced to metal with hydrogen.
Tungsten is rather resistant to attack by acids, except for mixtures of concentrated nitric and hydrofluoric acids, and it can be attacked rapidly by alkaline oxidizing melts, such as fused mixtures of potassium nitrate and sodium hydroxide or sodium peroxide; aqueous alkalies, however, are without effect. It is inert to oxygen at normal temperature but combines with it readily at red heat, to give the trioxides, and is attacked by fluorine at room temperature, to give the hexafluorides.
halogen lampHalogen lamp with tungsten filament.
Tungsten metal has a nickel-white to grayish lustre. Among metals it has the highest melting point, at 3,410 °C (6,170 °F), the highest tensile strength at temperatures of more than 1,650 °C (3,002 °F), and the lowest coefficient of linear thermal expansion (4.43 × 10−6 per °C at 20 °C [68 °F]). Tungsten is ordinarily brittle at room temperature. Pure tungsten can, however, be made ductile by mechanical working at high temperatures and can then be drawn into very fine wire. Tungsten was first commercially employed as a lamp filament material and thereafter used in many electrical and electronic applications. It is used in the form of tungsten carbide for very hard and tough dies, tools, gauges, and bits. Much tungsten goes into the production of tungsten steels, and some has been used in the aerospace industry to fabricate rocket-engine nozzle throats and leading-edge reentry surfaces. (For information on the mining, recovery, and applications of tungsten, see tungsten processing.)
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Learn MoreNatural tungsten is a mixture of five stable isotopes: tungsten-180 (0.12 percent), tungsten-182 (26.50 percent), tungsten-183 (14.31 percent), tungsten-184 (30.64 percent), and tungsten-186 (28.43 percent). Tungsten crystals are isometric and, by X-ray analysis, are seen to be body-centred cubic.