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 1910°C, 3470°F, 2183 K 
Period Boiling point 3407°C, 6165°F, 3680 K 
Block Density (g cm−3) 6.0 
Atomic number 23  Relative atomic mass 50.942  
State at 20°C Solid  Key isotopes 51
Electron configuration [Ar] 3d34s2  CAS number 7440-62-2 
ChemSpider ID 22426 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 is based on an 8th-century figurine of the Scandinavian goddess Freyja, after whom the element is named. It is set against a text from an Icelandic saga written in the 13th century.
Appearance
A silvery metal that resists corrosion.
Uses
About 80% of the vanadium produced is used as a steel additive. Vanadium-steel alloys are very tough and are used for armour plate, axles, tools, piston rods and crankshafts. Less than 1% of vanadium, and as little chromium, makes steel shock resistant and vibration resistant. Vanadium alloys are used in nuclear reactors because of vanadium’s low neutron-absorbing properties.

Vanadium(V) oxide is used as a pigment for ceramics and glass, as a catalyst and in producing superconducting magnets.
Biological role
Vanadium is essential to some species, including humans, although we need very little. We take in just 0.01 milligrams each day, and this is more than sufficient for our needs. In some compounds vanadium can become toxic.
Natural abundance
Vanadium is found in about 65 different minerals including vanadinite, carnotite and patronite. It is also found in phosphate rock, certain iron ores and some crude oils in the form of organic complexes.

Vanadium metal is obtained by reducing vanadium(V) oxide with calcium in a pressure vessel. Vanadium of high purity can be obtained by reducing vanadium(III) chloride with magnesium.
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History

Vanadium was discovered twice. The first time was in 1801 by Andrés Manuel del Rio who was Professor of Mineralogy in Mexico City. He found it in a specimen of vanadite, Pb5(VO4)3Cl and sent a sample to Paris. However, French chemists concluded that it was a chromium mineral.

The second time vanadium was discovered was in 1831 by the Swedish chemist Nil Gabriel Selfström at Stockholm. He separated it from a sample of cast iron made from ore that had been mined at Småland. He was able to show that it was a new element, and in so doing he beat a rival chemist, Friedrich Wöhler, to the discovery He was also working another vanadium mineral from Zimapan.

Pure vanadium was produced by Henry Roscoe at Manchester, in 1869, and he showed that previous samples of the metal were really vanadium nitride (VN).
 
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) 2.07 Covalent radius (Å) 1.44
Electron affinity (kJ mol−1) 50.655 Electronegativity
(Pauling scale)
1.63
Ionisation energies
(kJ mol−1)
 
1st
650.908
2nd
1410.423
3rd
2828.082
4th
4506.734
5th
6298.727
6th
12362.67
7th
14530.7
8th
16730.6
 

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 5, 4, 3, 2, 0
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  50V 49.947 0.25 1.4 x 1017 EC 
  51V 50.944 99.75
 

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 6.7
Crustal abundance (ppm) 138
Recycling rate (%) <10
Substitutability Low
Production concentration (%) 34
Reserve distribution (%) 36
Top 3 producers
  • 1) South Africa
  • 2) China
  • 3) Russia
Top 3 reserve holders
  • 1) China
  • 2) Russia
  • 3) South Africa
Political stability of top producer 44.3
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)
489 Young's modulus (GPa) 127.6
Shear modulus (GPa) 46.7 Bulk modulus (GPa) 158.0
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
- - - - 2.79
x 10-10
4.35
x 10-7
0.000107 0.00769 0.233 3.68 32.6
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Podcasts

Listen to Vanadium Podcast
Transcript :

Chemistry in its element: vanadium


(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 to an element with a role in body building and that's not just of the human kind. This is the stuff that was essential in helping to get the Model T Fords to first roll off of the production line because it strengthens steel. It's also the catalytic power behind the production of sulphuric acid and its named after the Norse God of beauty, love and fertility. And to reveal her identify here's Chris Orvig.

Chris Orvig

Vanadium, a first row transition metal in the Periodic Table, is an element of mystery. Not only was it first transported two hundred years ago from Mexico, and lost in a shipwreck along with all of the relevant lab notes by the great German scientist Baron von Humboldt, but it required discovery several times by such famous names as Wöhler, Berzelius and del Rio (who was actually talked out of his claim in 1805). Final and convincing verification came from the Swede Nils Sefström out of an oxide in iron ores in 1831. Vanadium metal was first prepared in the 1860s by English chemist Henry Enfield Roscoe. The place of vanadium as a trace element necessary for life processes has been just as tortuously argued and hotly debated through most of the last century - doubtless many organisms and other mammals require it.but do humans? A deficiency condition in humans has never been defined, but vanadium does have a medicinally relevant role as a potential treatment for diabetes mellitus, but more on this later.

Vanadium is the fifth most abundant transition metal in the earth's crust, often found with titanium and iron in their ores, and significant concentrations are found in certain coal and oil deposits, such as crude and shale oils. In its metallic state, it strengthens stainless steel and some superconducting alloys, while in its numerous ionic states it has been used spectroscopically to probe enzyme active sites and is found in both naturally occurring catalysts in seaweed and lab catalysts for oxidation chemistry. Silver vanadium oxides have a role in battery chemistry. The first large scale industrial use of vanadium metal was a century ago in the steels used to fashion the chassis of the Ford Model T car, and steel remains the main use of vanadium metal. Because vanadium is a light transition metal, not a "heavy metal" as often incorrectly claimed in the toxicology literature, vanadium metal contributes reduced weight to high tensile strength steels. The compound of greatest commercial importance is vanadium pentoxide, V2O5, which is used as a catalyst for the production of sulfuric acid, the bulk commodity chemical of greatest world production.

Tremendous versatility for an element named by Sefström for Vanadis (also known as Freyja) the Norse goddess of beauty, love and fertility. All seven oxidation states from -1 to +5 are known in inorganic chemistry, and give rise to the many beautiful colours often associated with transition metal compounds. Its multiple oxidation states, ready hydrolysis and polymerisation bestow upon vanadium a chemistry far richer and more complex than that of many elements, formation of aggregated oxyanions and sulfur complexes being just two examples. The highest three oxidation states (III, IV and V) are of significant importance in water and are the oxidation states found in the more than one hundred known vanadium minerals. The tar sands of Alberta in western Canada present a huge untapped reservoir of vanadium.

Certain marine ascidians and sea squirts concentrate vanadium up to one million fold from surrounding seawater, while mushroom species such as amanita muscaria concentrate vanadium(IV); in both cases the reasons have yet to be elucidated. Biology exploits vanadium's oxidation state promiscuity in the vanadium-dependent haloperoxidases, which were discovered in marine brown algae and seaweed in the 1980s; these are surprisingly robust marine enzymes that oxidise substrates using peroxide as an electron acceptor. There is even a vanadium nitrogenase - a vanadium nitrogen-reducing alternative to the iron-molybdenum enzyme that reduces dinitrogen to ammonia in the root-nodules of many plants.

Most conveniently for studies of vanadium(V) chemistry (that which is important in oxidation catalysis), naturally occurring vanadium is mono-isotopic - vanadium-51 has a nuclear spin of 7/2 which is useful for NMR spectroscopy. Vanadium(IV) has one unpaired 3d electron that, coupled with the nuclear spin, is exquisitely diagnostic in EPR spectroscopy - the vanadyl ion (VO2+) is a sensitive spectroscopic probe that has been used to elucidate enzyme active site structure, as well as catalytic activity.

Vanadium has significant effects on cellular growth, redox and signaling processes, as well as enzyme function. Vanadyl sulphate is a very controversial dietary supplement, popular in body-building and can often be purchased in gym shops where allowed by law. The vanadate anion is a phosphate mimic that has been used as a probe of the enzymes that transfer phosphates in cell signaling - the phosphatases and kinases. Not surprisingly vanadium shows many interesting biological properties resulting from this activity, not the least of which is its ability to enhance, but not mimic, the action of insulin, the key hormone in diabetes mellitus. This property was first shown in France in three diabetic humans and published in 1899 in La Presse Médicale. Vanadium does not act in the complete absence of insulin - hence it is an enhancer rather than a mimic of insulin. Significant efforts over the last 25 years, since John McNeill of the University of British Columbia showed that vanadate was effective in a diabetic rat model, have led to a number of vanadium compounds now being clinically investigated in humans as potential agents for the treatment of diabetes.

Chris Smith

A colourful transition metal with a sweet side. That was chemist Chris Orvig and he's based at the University of British Columbia. Next week you'll have to be sure to hold your nose.

Bernard J Bulkin

Butyl seleno mercaptan is the essential ingredient of skunk smell, and is certainly a contender for the title of the worst smelling compound. Once you have smelt it you will never forget it, nor underestimate the impact that this interesting element can have.

Chris Smith

Yuk, but thankfully you can catch up with the whole story of selenium and without having to have an unforgettable encounter with a skunk and that's all on next week's Chemistry in its Element. 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.