Periodic Table > Bohrium
 

Terminology


Allotropes
Some elements exist in several different structural forms, these are called allotropes.


For more information on Murray Robertson’s image see Uses/Interesting Facts below.

 

Fact Box Terminology


Group
Elements appear in columns or ‘groups’ in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell.


Period
Elements are laid out into rows or ‘periods’ so that similar chemical behaviour is observed in columns.


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, principal, diffuse, and fundamental.


Atomic Number
The number of protons in the nucleus.


Atomic Radius/non -bonded (Å)
based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties, for more details please refer to the CRC Handbook of Chemistry and Physics.


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


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.


Melting Point (oC)
The temperature at which the solid-liquid phase change occurs.


Melting Point (K)
The temperature at which the solid-liquid phase change occurs.


Melting Point (oF)
The temperature at which the solid-liquid phase change occurs.


Boiling Point (oC)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (K)
The temperature at which the liquid-gas phase change occurs.


Boiling Point (oF)
The temperature at which the liquid-gas phase change occurs.


Sublimation
Elements that do not possess a liquid phase at atmospheric pressure (1 atm) are described as going through a sublimation process.


Density (kgm-3)
Density is the weight of a substance that would fill 1 m3 (at 298 K unless otherwise stated).


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.


Key Isotopes (% abundance)
An element must by definition have a fixed number of protons in its nucleus, and as such has a fixed atomic number, however variants of an element can exist with differing numbers of neutrons, and hence a different atomic masses (e.g. 12C has 6 protons and 6 neutrons and 13C has 6 protons and 7 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 (where several isotopes exist, a value is presented for the most prevalent isotope).

Fact Box

 
Group Melting point Unknown 
Period Boiling point Unknown 
Block Density (kg m-3) Unknown 
Atomic number 107  Relative atomic mass 264.125  
State at room temperature Solid  Key isotopes 272Bh 
Electron configuration [Rn] 5f146d57s2  CAS number 54037-14-8 
ChemSpider ID - ChemSpider is a free chemical structure database
 

Interesting Facts terminology


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.


Natural Abundance

Where this element is most commonly found in nature.


Biological Roles

The elements role within the body of humans, animals and plants. Also functionality in medical advancements both today and years ago.


Appearance

The description of the element in its natural form.

Uses / Interesting Facts

 
Image explanation
Abstracted symbol and patterns based on the now iconic atomic model proposed by Neils Bohr in 1913
Appearance
A highly radioactive metal that does not occur naturally and of which only a few atoms have ever been made. It is of research interest only.
Uses
At present, it is only used in research.
Biological role
None
Natural abundance
A transuranium element, only a few atoms of bohrium have ever been made, and it will probably never be isolated in observable quantities. Created by the so-called “cold fusion” method, in which a target of bismuth is bombarded with atoms of chromium.
 
Atomic Data Terminology

Atomic radius/non -bonded (Å)
Based on Van der Waals forces (where several isotopes exist, a value is presented for the most prevalent isotope). These values were calculated using a multitude of methods including crystallographic data, gas kinetic collision cross sections, critical densities, liquid state properties,for more details please refer to the CRC Handbook of Chemistry and Physics.


Electron affinity (kJ mol-1)
The energy released when an additional electron is attached to the neutral atom and a negative ion is formed (where several isotopes exist, a value is presented for the most prevalent isotope). *


Electronegativity (Pauling scale)
The degree to which an atom attracts electrons towards itself, expressed on a relative scale as a function bond dissociation energies, Ed in eV. χA - χB =(eV)-1/2sqrt(Ed(AB)-[Ed(AA)+Ed(BB)]/2), with χH set as 2.2 (where several isotopes exist, a value is presented for the most prevalent isotope).


1st Ionisation energy (kJ mol-1)
The minimum energy required to remove an electron from a neutral atom in its ground state (where several isotopes exist, a value is presented for the most prevalent isotope).


Covalent radius (Å)
The size of the atom within a covalent bond, given for typical oxidation number and coordination (where several isotopes exist, a value is presented for the most prevalent isotope). ***

Atomic Data

 
Atomic radius, non-bonded (Å) Unknown Covalent radius (Å) 1.41
Electron affinity (kJ mol-1) Unknown Electronegativity
(Pauling scale)
Unknown
Ionisation energies
(kJ mol-1)
 
1st
-
2nd
-
3rd
-
4th
-
5th
-
6th
-
7th
-
8th
-
 

Mining/Sourcing Information

Data for this section of the data page has been provided by the British Geological Survey. To review the full report please click here or please look at their website here.


Key for numbers generated


Governance indicators

1 (low) = 0 to 2

2 (medium-low) = 3 to 4

3 (medium) = 5 to 6

4 (medium-high) = 7 to 8

5 (high) = 9


Reserve base distribution

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %

(Where data are unavailable an arbitrary score of 2 was allocated. For example, Be, As, Na, S, In, Cl, Ca and Ge are allocated a score of 2 since reserve base information is unavailable. Reserve base data are also unavailable for coal; however, reserve data for 2008 are available from the Energy Information Administration (EIA).)


Production Concentration

1 (low) = 0 to 30 %

2 (medium-low) = 30 to 45 %

3 (medium) = 45 to 60 %

4 (medium-high) = 60 to 75 %

5 (high) = 75 %


Crustal Abundance

1 (low) = 100 to 1000 ppm

2 (medium-low) =10 to 100 ppm

3 (medium) = 1 to 10 ppm

4 (medium-high) = 0.1 to 1 ppm

5 (high) = 0.1 ppm

(Where data are unavailable an arbitrary score of 2 was allocated. For example, He is allocated a score of 2 since crustal abundance data is unavailable.)


Explanations for terminology


Crustal Abundance (ppm)

The abundance of an element in the Earth's crust in parts-per-million (ppm) i.e. The number of atoms of this element per 1 million atoms of crust.


Sourced

The country with the largest reserve base.


Reserve Base Distribution

This is a measure of the spread of future supplies, recording the percentage of a known resource likely to be available in the intermediate future (reserve base) located in the top three countries.


Production Concentrations

This reports the percentage of an element produced in the top three countries. The higher the value, the larger risk there is to supply.


Total Governance Factor

The World Bank produces a global percentile rank of political stability. The scoring system is given below, and the values for all three production countries were summed.


Relative Supply Risk Index

The Crustal Abundance, Reserve Base Distribution, Production Concentration and Governance Factor scores are summed and then divided by 2, to provide an overall Relative Supply Risk Index.

Supply Risk

 
Scarcity factor Unknown
Country with largest reserve base Unknown
Crustal abundance (ppm) Unknown
Leading producer Unknown
Reserve base distribution (%) Unknown
Production concentration (%) Unknown
Total governance factor(production) Unknown
Top 3 countries (mined)
  • Unknown
Top 3 countries (production)
  • Unknown
 

Oxidation states/ Isotopes


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

Terminology


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. Free atoms have an oxidation state of 0, and the sum of oxidation numbers within a substance must equal the overall charge.


Important Oxidation states
The most common oxidation states of an element in its compounds.


Isotopes
Elements are defined by the number of protons in its centre (nucleus), whilst the number of neutrons present can vary. The variations in the number of neutrons will create elements of different mass which are known as isotopes.

Oxidation States / Isotopes

 
Common oxidation states Unknown
Isotopes Isotope Atomic mass Natural abundance (%) Half life Mode of decay
  272Bh 272.138 - ~ 10 s  α 
 

Pressure and Temperature - Advanced Terminology


Molar Heat Capacity (J mol-1 K-1)

Molar heat capacity is the energy required to heat a mole of a substance by 1 K.


Young's modulus (GPa)

Young's modulus is a measure of the stiffness of a substance, that is, 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 (GPa)

The shear modulus of a material is a measure of how difficult it is to deform a material, and is given by the ratio of the shear stress to the shear strain.


Bulk modulus (GPa)

The bulk modulus is a measure of how difficult to compress a substance. Given by the ratio of the pressure on a body to the fractional decrease in volume.


Vapour Pressure (Pa)

Vapour pressure is the 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 / Temperature - Advanced

 
Molar heat capacity
(J mol-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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History

In 1975 a team led by Yuri Oganessian at the Russian Joint Institute for Nuclear Research (JINR) in Dubna, bombarded bismuth with chromium and produced element 107, isotope-261. They published the results of their successful run in 1976 and submitted a discovery claim.


In 1981, a team led by Peter Armbruster and Gottfried Münzenberg at the German nuclear research institute the Geselleschaft für Schwerionenforschung (GSI) bombarded bismuth with chromium and they succeeded in making a single atom of isotope 262. Now followed a period of negotiation to establish who discovered elements 107 first and thereby had the right to name it.


The International Union of Pure and Applied Chemistry (IUPAC) said that the GSI should be awarded the discovery because they had the more credible submission, but that the JINR were probably the first to make it.

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Podcasts

Listen to Bohrium Podcast
Transcript :

Chemistry in its element - bohrium


(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 are fusing nuclei. Erric Scerri.

 

Eric Scerri

 

A total of 25 transuranium elements have now been artificially synthesised, starting with neptunium element 93 and ending with the as yet unnamed element 118.   This includes the most recently announced element of all, element 117 that was synthesised in April 2010.  

 

This podcast is about one of these elements, number 107 in the periodic table, called bohrium.   Transuranium elements are essentially made by slamming atoms of different elements into each other at very high speeds in the hope that such collisions will allow nuclei to fuse together to form atoms of a new element. 

 

The few atoms that ever form in this way are very unstable and typically decay with half-lives of seconds or fractions of a second.   Lay persons often wonder why such experiments are important since practical applications of the elements that are man-made are generally out of the question.   The answer is that the experiments are of scientific importance since they allow one to verify theoretical predictions.   Element 107 has had a special role to play in this respect and I will return to this in a moment.  

 

Bohrium is also special in another respect, as the first element to be synthesised by a cold - rather than hot - fusion process between two nuclei.   The idea is to make two nuclei collide at low excitation energies and consequently to capitalise on the reduced tendency of such combined atoms to disintegrate.   Incidentally, this kind of cold fusion has no connection to the alleged cold-fusion that was announced in 1989 by Martin Fleischmann and Stanley Pons who reported that they had produced fusion in a tabletop experiment using heavy water.

 

The successful cold fusion synthesis of bohrium was first achieved in 1981 in Darmstadt, Germany, by the fusion of bismuth-209 with chromium-24 to form bohrium-262 with a half life of about 85 milliseconds.   Since then many other isotopes of bohrium have been produced, including the longest lived isotope so far bohrium-270, with a half life of 61 seconds. 

 

The element's discoverers wanted to call it nielsbohrium after the great 20th century Danish physicist. But Iupac, the official body that governs the naming of elements, ruled against this name on the grounds that no element had ever been given the full name of a scientist.   Instead they proposed bohrium, which became the officially recognised name in 1997.  

 

In the periodic table bohrium lies below chromium, technetium and rhenium in group 6.   However, the application of the theory of relativity to calculations involving very heavy atoms like bohrium leads to predictions of anomalous behaviour which suggests that they do not behave as typical members of the groups that they lie in.   For example, the discovery of elements 104 and 105, rutherfordium and dubnium respectively, and chemical experiments conducted on them, strongly suggested that relativistic effects were causing these elements to behave in anomalous ways and not as expected according to their places in the periodic table.   It began to look as if the periodic law, of which the periodic table is a graphic representation, had met its match.  

 

It was only when the chemistry of elements 106 and 107, or seaborgium and bohrium respectively, were examined that it became clear that the periodic law was not being over-turned by relativistic effects.   Quantitative experiments on the properties of the oxychloride of bohrium, in particular, showed that the element was behaving almost exactly that one would have predicted from its position below technetium and rhenium in the periodic table.   In fact an article describing the chemistry of bohrium that appeared in the journal Nature with the title 'Boring bohrium', referring to the fact that bohrium was behaving as expected and not showing the exotic signs of relativistic effects.  

 

It is quite remarkable that the periodic law that was discovered over 140 years ago has not been overturned by quantum mechanics or by the theory of relativity which date from more recent times and which one might suppose to have penetrated into the secrets of nature to a greater degree.   Or perhaps it is just that the phenomenon of chemical periodicity as embodied by the periodic table represents a completely universal and fundamental principle of nature.       

 

Meera Senthilingam

 

So the impressive accuracy of chemical periodicity. That was UCLA scientist and author Eric Scerri with the lawful chemistry of bohrium. Now next week we flash back to a memorable decade. 

 

Anna Lewcock

 

Do you remember the 80s? The leg warmers, the big hair, the shoulder pads? Many fashion crimes were committed and statements made as a generation fought to carve out its identity.

 

Looking back on those photos a couple of decades down the line, some might wish they hadn't fought so hard. But it's not just rebellious teenagers or disillusioned 40-somethings that suffer identity crises - elements can too.

 

Meera Senthilingam

 

And to discover the crises that face the element hassium join the RSC's Anna Lewcock in next week's Chemistry in its element. Until then thank you for listening, I'm Meera Senthilingam.

 

(Promo) 

Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists dot com. There's more information and other episodes of Chemistry in its element on our website at chemistryworld dot org forward slash elements. 

(End promo)

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Resources

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Assessment for Learning is an effective way of actively involving students in their learning. This is a series of plans based around chemistry topics.
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The Periodic Table allows chemists to see similarities and trends in the properties of chemical elements. This experiment illustrates some properties of the common transition elements and their compo...
Description :
In this experiment you will be looking at a group of transition elements chromium, molybdenum and tungsten.
Description :
The purpose of this experiment is to examine some of the solution chemistry of the transition elements.
 

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References

 
Images:  Visual Elements © Murray Robertson 2011
Mining and Sourcing data:  British Geological Survey – natural environment research council.
Text:  John Emsley Nature’s Building Blocks: An A-Z Guide to the Elements, Oxford University Press, 2nd Edition, 2011.
Additional information for platinum, gold, neodymium and dysprosium obtained from Material Value Consultancy Ltd www.matvalue.com
Data: CRC Handbook of Chemistry and Physics, CRC Press, 92nd Edition, 2011.
G. W. C. Kaye and T. H. Laby Tables of Physical and Chemical Constants, Longman, 16th Edition, 1995.
Members of the RSC can access these books through our library.