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 Unknown 
Period Boiling point Unknown 
Block Density (g cm−3) Unknown 
Atomic number 104  Relative atomic mass [267]  
State at 20°C Solid  Key isotopes 265Rf 
Electron configuration [Rn] 5f146d27s2  CAS number 53850-36-5 
ChemSpider ID 11201447 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 abstract metallic symbol and background are inspired by imagery from early and modern particle accelerators.
Appearance
A radioactive metal that does not occur naturally. Relatively few atoms have ever been made.
Uses
At present, it is only used in research.
Biological role
Rutherfordium has no known biological role.
Natural abundance
Rutherfordium is a transuranium element. It is created by bombarding californium-249 with carbon-12 nuclei.
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History

In 1964, a team led by Georgy Flerov at the Russian Joint Institute for Nuclear Research (JINR) in Dubna, bombarded plutonium with neon and produced element 104, isotope 259. They confirmed their findings in 1966.

In 1969, a team led by Albert Ghiorso at the Californian Lawrence Berkeley Laboratory (LBL) made three successful attempts to produce element 104: by bombarding curium with oxygen to get isotope-260, californium with carbon to get isotope-257, and californium with carbon to get isotope-258.

A dispute over priority of discovery followed and eventually, in 1992, the International Unions of Pure and Applied Chemistry (IUPAC) concluded that both the Russian and American researchers had been justified in making their claims. IUPAC decided element 104 would be called rutherfordium.
 
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) Unknown Covalent radius (Å) 1.57
Electron affinity (kJ mol−1) Unknown Electronegativity
(Pauling scale)
Unknown
Ionisation energies
(kJ mol−1)
 
1st
579
2nd
-
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 Unknown
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  265Rf 265.117 - ~ 2 m  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.


 

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)
Unknown Young's modulus (GPa) Unknown
Shear modulus (GPa) Unknown Bulk modulus (GPa) Unknown
Vapour pressure  
Temperature (K)
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
Pressure (Pa)
- - - - - - - - - - -
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Podcasts

Listen to Rutherfordium Podcast
Transcript :

Chemistry in its element: rutherfordium


(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)

Meera Senthilingam

This week we find out how the elements beyond the actinides were discovered. Revealing the chemistry of the first transactinide rutherfordium, here's Simon Cotton.

Simon Cotton

When the last member of the actinide series, element 103 or lawrencium, was discovered, I was at school doing my A-levels, and I remember reading about it in the magazine Scientific American. The isotope found had a mass of 258 and it didn't hang about for long - having a half-life of just 3.8 seconds. This was not unexpected as half lives had been getting shorter right along the actinide series.

This discovery prompted the scientific community to start asking, are there any elements waiting to be made beyond lawrencium? And if so, where would they fit in the periodic table?

In those days, scientific competition between Russia and America was intense, and over the next few years both Russian and American nuclear scientists had a bash at element 104.

Both of them used the nuclear equivalent of a shooting gallery. They fired nuclear bullets, the positive ions of light atoms at targets. The targets weren't moving ducks, but stationary targets of very heavy nuclei.

What they had to do was to overcome the repulsion between the positive nucleus of the target atom and the positive projectile, so that the two nuclei fused together to make the new heavier atom. And both groups took different approaches.

The Russians went first, firing neon-22 ions at a target of plutonium-242. The reaction products were immediately chlorinated, and the team claimed they had made a new element which had formed a volatile chloride, though they were not clear about which isotope they might have made, or even its half-life.

Three years later, an American team bombarded californium-249 with carbon-12 ions, and were confident they had made rutherfordium-257, identifying its alpha-decay product, an isotope of nobelium. This was confirmed by a different American team in 1973. Subsequently rutherfordium was also made in 1985 by a German team at Darmstadt, who bombarded a lead-208 target with titanium-50 ions, in other words a lighter target but a heavier projectile.

Since it wasn't clear who the true 'discoverer' was, both the Americans and the Russians suggested names for element 104. The Americans called it rutherfordium, after Ernest Rutherford, who pioneered the planetary model of the atom and discovered nuclear fission, whilst the Russians chose kurchatovium after Igor Vasilyevich Kurchatov, a pioneering Russian nuclear physicist who led the project to make the first Russian atom bomb. After much dispute, IUPAC, the institute who officially names new elements, selected the name Rutherfordium.

Several isotopes of rutherfordium have half-lives in the order of seconds, making chemical experiments possible before the atoms decay. Rutherfordium-261 has a half-life of just over a minute; rutherfordium-263 has a half-life of 10 minutes and rutherfordium-267 may have a half life of over an hour, but so far the experiments have to be carried out with the lighter isotopes that are easier to make, like rutherfordium-261.

Because it has been around for longer and its isotopes are better known, more is known about the chemistry of rutherfordium than of any succeeding element. Working with rutherfordium requires specialist methods and knowledge, as it involves working with tiny quantities of very short-lived, radioactive atoms. This means that as soon as a new atom has been made, it has to be whipped away from the action before it decays. So new atoms of rutherfordium have to be collected as soon as they recoil from the target, and then be transported by an aerosol before being chlorinated and chromatographed before passing to a detector. It has been found that in solution, rutherfordium behaves very similarly to zirconium and hafnium, but unlike the trivalent actinides, leading chemists to concluded that rutherfordium belongs in the same group as Zr and Hf, rather than being a kind of super-actinide.

It also forms quite strong chloride complexes in solution, again resembling zirconium and hafnium rather than the actinides or Group I and II metals. Rutherfordium chloride is believed to be RfCl4. It condenses around 220°C, similar to zirconium chloride but more volatile than hafnium chloride and much more volatile than the actinide tetrachlorides. Similarly rutherfordium bromide is more volatile than hafnium bromide.

So even though it is extremely unlikely that enough of any rutherfordium compound is going to be isolated in visible quantities, we do know enough to see which family rutherfordium belongs in. That's another triumph for our understanding of the periodic table.

Meera Senthilingam

Triumph indeed when the half lives of the isotopes involved are a matter of seconds. That was Uppingham School's Simon Cotton with the chemistry of the first transactinide rutherfordium. Now next week an element that some may unfairly consider useless when it certainly does have its uses.

Brian Clegg

For a long time thulium was a Cinderella substance. There was nothing you could do with thulium that couldn't be done better and cheaper with one of the other elements. It's notable that one science writer has said of thulium 'the most surprising thing about it is there's nothing surprising about it.' But that's a little unfair. Thulium 170 with a half life of 128 days, produced by bombarding thulium in a nuclear reactor, has proved a good portable source of X-rays. It was first suggested for this role in the 1950s and has frequently turned up since in small scale devices, such as those used in dentist's surgeries, but also find it cropping up in engineering, where the X-rays can be used to hunt for cracks in components.

Meera Senthilingam

And join Brian Clegg to find out how this rare earth element was discovered and why it's considered more valuable than platinum in next week's Chemistry in its element. Until then I'm Meera Senthilingam and thank you for listening.

(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.