Glossary


Allotropes
Some elements exist in several different structural forms, called allotropes. Each allotrope has different physical properties.


For more information on the Visual Elements image see the Uses and properties section below.

 

Glossary


Group
A vertical column in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.


Period
A horizontal row in the periodic table. The atomic number of each element increases by one, reading from left to right.


Block
Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f).


Atomic number
The number of protons in an atom.


Electron configuration
The arrangements of electrons above the last (closed shell) noble gas.


Melting point
The temperature at which the solid–liquid phase change occurs.


Boiling point
The temperature at which the liquid–gas phase change occurs.


Sublimation
The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.


Density (g cm−3)
Density is the mass of a substance that would fill 1 cm3 at room temperature.


Relative atomic mass
The mass of an atom relative to that of carbon-12. This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists, the value given is the abundance weighted average.


Isotopes
Atoms of the same element with different numbers of neutrons.


CAS number
The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems.


Fact box

Group Melting point 3414°C, 6177°F, 3687 K 
Period Boiling point 5555°C, 10031°F, 5828 K 
Block Density (g cm−3) 19.3 
Atomic number 74  Relative atomic mass 183.84  
State at 20°C Solid  Key isotopes 182W, 184W, 186
Electron configuration [Xe] 4f145d46s2  CAS number 7440-33-7 
ChemSpider ID 22403 ChemSpider is a free chemical structure database
 

Glossary


Image explanation

Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.


Appearance

The description of the element in its natural form.


Biological role

The role of the element in humans, animals and plants.


Natural abundance

Where the element is most commonly found in nature, and how it is sourced commercially.

Uses and properties

Image explanation
The symbol used reflects the once common use of the element in light bulbs.
Appearance
A shiny, silvery-white metal.
Uses
Tungsten was used extensively for the filaments of old-style incandescent light bulbs, but these have been phased out in many countries. This is because they are not very energy efficient; they produce much more heat than light.

Tungsten has the highest melting point of all metals and is alloyed with other metals to strengthen them. Tungsten and its alloys are used in many high-temperature applications, such as arc-welding electrodes and heating elements in high-temperature furnaces.

Tungsten carbide is immensely hard and is very important to the metal-working, mining and petroleum industries. It is made by mixing tungsten powder and carbon powder and heating to 2200°C. It makes excellent cutting and drilling tools, including a new ‘painless’ dental drill which spins at ultra-high speeds.

Calcium and magnesium tungstates are widely used in fluorescent lighting.
Biological role
Tungsten is the heaviest metal to have a known biological role. Some bacteria use tungsten in an enzyme to reduce carboxylic acids to aldehydes.
Natural abundance
The principal tungsten-containing ores are scheelite and wolframite. The metal is obtained commercially by reducing tungsten oxide with hydrogen or carbon.
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History

More than 350 years ago, porcelain makers in China incorporated a unique peach colour into their designs by means of a tungsten pigment that was not known in the West. Indeed it was not for another century that chemists in Europe became aware of it. In 1779, Peter Woulfe examined a mineral from Sweden and concluded it contained a new metal, but he did not separate it. Then in 1781, Wilhelm Scheele investigated it and succeeded in isolating an acidic white oxide and which he rightly deduced was the oxide of a new metal.

The credit for discovering tungsten goes to the brothers, Juan and Fausto Elhuyar, who were interested in mineralogy and were based at the Seminary at Vergara, in Spain, 1783 they produced the same acidic metal oxide and even reduced it to tungsten metal by heating with carbon.
 
Glossary

Atomic radius, non-bonded
Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced. These values were determined using several different methods.


Covalent radius
Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination.


Electron affinity
The energy released when an electron is added to the neutral atom and a negative ion is formed.


Electronegativity (Pauling scale)
The tendency of an atom to attract electrons towards itself, expressed on a relative scale.


First ionisation energy
The minimum energy required to remove an electron from a neutral atom in its ground state.

Atomic data

Atomic radius, non-bonded (Å) 2.18 Covalent radius (Å) 1.50
Electron affinity (kJ mol−1) 78.757 Electronegativity
(Pauling scale)
1.7
Ionisation energies
(kJ mol−1)
 
1st
758.764
2nd
1553.4
3rd
-
4th
-
5th
-
6th
-
7th
-
8th
-
 

Glossary


Common oxidation states

The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge.


Isotopes

Atoms of the same element with different numbers of neutrons.


Key for isotopes


Half life
  y years
  d days
  h hours
  m minutes
  s seconds
Mode of decay
  α alpha particle emission
  β negative beta (electron) emission
  β+ positron emission
  EC orbital electron capture
  sf spontaneous fission
  ββ double beta emission
  ECEC double orbital electron capture

Oxidation states and isotopes

Common oxidation states 6, 5, 4, 3, 2, 0
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  180W 179.947 0.12 1.8 x 1018 α 
  182W 181.948 26.5 > 7.7 x 1021 α 
  183W 182.950 14.31 > 4.1 x 1021 α 
  184W 183.951 30.64 > 8.9 x 1021 α 
  186W 185.954 28.43 > 8.2 x 1021 α 
 

Glossary

Data for this section been provided by the British Geological Survey.


Relative supply risk

An integrated supply risk index from 1 (very low risk) to 10 (very high risk). This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores.


Crustal abundance (ppm)

The number of atoms of the element per 1 million atoms of the Earth’s crust.


Recycling rate

The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply.


Substitutability

The availability of suitable substitutes for a given commodity.
High = substitution not possible or very difficult.
Medium = substitution is possible but there may be an economic and/or performance impact
Low = substitution is possible with little or no economic and/or performance impact


Production concentration

The percentage of an element produced in the top producing country. The higher the value, the larger risk there is to supply.


Reserve distribution

The percentage of the world reserves located in the country with the largest reserves. The higher the value, the larger risk there is to supply.


Political stability of top producer

A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators.


Political stability of top reserve holder

A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.


Supply risk

Relative supply risk 9.5
Crustal abundance (ppm) 1
Recycling rate (%) 10–30
Substitutability High
Production concentration (%) 84
Reserve distribution (%) 61
Top 3 producers
  • 1) China
  • 2) Russia
  • 3) Bolivia
Top 3 reserve holders
  • 1) China
  • 2) Russia
  • 3) USA
Political stability of top producer 24.1
Political stability of top reserve holder 24.1
 

Glossary


Specific heat capacity (J kg−1 K−1)

Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K.


Young's modulus

A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.


Shear modulus

A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain.


Bulk modulus

A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume.


Vapour pressure

A measure of the propensity of a substance to evaporate. It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system.

Pressure and temperature data – advanced

Specific heat capacity
(J kg−1 K−1)
132 Young's modulus (GPa) 411.0
Shear modulus (GPa) 160.6 Bulk modulus (GPa) 311.0
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
- - - - - - - - 2.62
x 10-10
3.01
x 10-8
1.59
x 10-6
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Podcasts

Listen to Tungsten Podcast
Transcript :

Chemistry in its element: tungsten


(Promo)

You're listening to Chemistry in its element brought to you by Chemistry World, the magazine of the Royal Society of Chemistry.

(End promo)

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.

(Promo)

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.

(End promo)
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Resources

Learn Chemistry: Your single route to hundreds of free-to-access chemistry teaching resources.
 

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References

Visual Elements images and videos
© Murray Robertson 1998-2017.

 

Data

W. M. Haynes, ed., CRC Handbook of Chemistry and Physics, CRC Press/Taylor and Francis, Boca Raton, FL, 95th Edition, Internet Version 2015, accessed December 2014.
Tables of Physical & Chemical Constants, Kaye & Laby Online, 16th edition, 1995. Version 1.0 (2005), accessed December 2014.
J. S. Coursey, D. J. Schwab, J. J. Tsai, and R. A. Dragoset, Atomic Weights and Isotopic Compositions (version 4.1), 2015, National Institute of Standards and Technology, Gaithersburg, MD, accessed November 2016.
T. L. Cottrell, The Strengths of Chemical Bonds, Butterworth, London, 1954.

 

Uses and properties

John Emsley, Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, New York, 2nd Edition, 2011.
Thomas Jefferson National Accelerator Facility - Office of Science Education, It’s Elemental - The Periodic Table of Elements, accessed December 2014.
Periodic Table of Videos, accessed December 2014.

 

Supply risk data

Derived in part from material provided by the British Geological Survey © NERC.

 

History text

Elements 1-112, 114, 116 and 117 © John Emsley 2012. Elements 113, 115, 117 and 118 © Royal Society of Chemistry 2017.

 

Podcasts

Produced by The Naked Scientists.

 

Periodic Table of Videos

Created by video journalist Brady Haran working with chemists at The University of Nottingham.