Periodic Table > Dubnium
 

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 105  Relative atomic mass 262.114  
State at room temperature Solid  Key isotopes 268Db 
Electron configuration [Rn] 5f146d37s2  CAS number 53850-35-4 
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
The image features a stylized cyrillic character version of “Dubna” against an abstracted “fractal particle” background.
Appearance
A highly radioactive metal which 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 created by bombarding 249Cf with 15N nuclei.
 
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) 1.49
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
  268Db 268.125 - 1.2 d  fs, EC 
 

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 1968, a team led by Georgy Flerov at the Russian Joint Institute for Nuclear Research (JINR) bombarded americium with neon and made an isotope of element 105. In 1970, a team led by Albert Ghiorso at the American Lawrence Berkeley Laboratory (LBL) bombarded californium with neon and obtained isotope 261. They disputed the claim of the JINR people. The two groups gave it different names. The Russians called it neilsbohrium, while the Americans called it hahnium, both being derived from the names of prominent nuclear scientists.


Eventually, the International Union of Pure and Applied Chemistry (IUPAC) decided it should be called dubnium.

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Podcasts

Listen to Dubnium Podcast
Transcript :

Chemistry in Its Element - Dubnium


(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 Senthilingham

This week: warfare, as the US and Russia fight to find new elements. Simon Cotton:

 

Simon Cotton

In the days of the Cold War, America and Russia rivalled each other in all sorts of ways. Never mind thermonuclear bombs and intercontinental ballistic missiles to deliver them, they competed in putting men and women into space; who could win the most medals in the Olympic Games; and in making new chemical elements. In the case of element 105, the controversy went on for nearly 30 years and was part of the so-called 'Transfermium Wars', when no blood was spilt but a great deal of ink was.

In the Red corner, the Soviet team at the Joint Institute for Nuclear Research at Dubna, near Moscow, led by Georgy Flerov. In the Blue corner, the American team at the University of California at Berkeley, led by Albert Ghiorso.

In 1968, the Soviet team bombarded an americium-243 target with neon-22 and claimed to have made isotopes of mass 260 or 261 of element 105. First round to Russia. Two years later, the Berkeley group reported bombarding californium 249 with nitrogen-15, and claimed they had made an isotope of element 105 of mass 260 with a half life of around 1.5 seconds. They showed its alpha-decay product was element 103, Lawrencium. They gave it the name hahnium, after Otto Hahn, who received the 1944 Nobel Prize in Chemistry for the discovery of nuclear fission. Lise Meitner, a collaborator of Hahn, who had predicted fission, did not get even a mention from the Nobel committee, but more on this later. Also in 1970, the Russians reported more results, with more convincing data. They named it nielsbohrium, after the Danish physicist who was awarded the 1922 Nobel Prize for Physics for his researches on atomic structure and radiation.

As time went on, studies from both laboratories continued, and evidence mounted that element 105 resembled niobium and tantalum, being a member of a 6d transition series. In 1986, the Transfermium Working Group was set up to determine firstly, the criteria that must be satisfied for the discovery of a new chemical element to be recognised and secondly to apply these criteria to the discovery of the transfermium elements. For the time being, in view of the conflicting claims, they kicked for touch and proposed a temporary name of unnilpentium (symbol Unp) while they decided who had synthesised and characterised this element. In 1994, they suggested the name joliotium (Jl), after the French physicist Frederic Joliot-Curie, but this did not find acceptance. Finally in 1997, the working group recognised that both Berkeley and Dubna had made 'significant contributions' to the discovery of elements 104 and 105, and said that since the Berkeley contributions were recognised in the names of elements 104 and 106 (Rutherfordium and Seaborgium), element 105 should be given the name dubnium, symbol Db, after the town the Russian scientists came from.

Although only a few atoms have ever been made, we know a bit about the chemistry of dubnium. We think that its aqua ion adopts the +5 oxidation state, as the dubnium aqua ion is adsorbed onto glass from solution, just like niobium and tantalum above it in Group 5 - but unlike +3 and +4 ions of lanthanide and actinide metals. Attempts to form fluoride complexes in solution suggest that Db resembles niobium more than tantalum. Chemists have also made some chlorides and bromides, though they may possibly have been studying oxyhalides.

Element 105 has had five names in total, being reinvented almost as often as Madonna. 

I mentioned earlier that the American team called it hahnium until 1997; well, now it has been rejected, this name can never be used for the name of an element, whereas in 1997 meitnerium was adopted as the name for element 109. That's right, Otto Hahn got a Nobel prize but no element named after him, whereas Lise Meitner, his co-worker, got no Nobel prize, but an element named after her. In the words that William Shakespeare puts into the mouth of a clown in Twelfth Night 'the whirligig of time brings in his revenges'.

 

Meera Senthilingham

So all is fair in the world of chemistry, kind of. That was Uppingham School's Simon Cotton bringing us the competitive discovery of dubnium. Now, staying with the transactinides, and the much deserved recognition of Lise Meitner; next week, we discover the chemistry of Meitnerium

 

Nik Kaltsoyannis 

Meitnerium and the other transactinide elements do not exist in ature. They are all man made and have been synthesised in only fantastically small quantities, by combining the atoms of two lighter elements. They are all highly radioactive, with very short half lives, severely limiting the practical chemistry that can be performed on them. Indeed, entirely new experimental techniques, collectively known as "atom at a time" methods, have been developed to study these elements. In these experiments we are not working with moles of atoms, or even recognisable fractions of moles, but literally with single atoms.

 

Meera Senthilingham

And to find out how these techniques can be performed with such precision, join UCL's Nik Kaltsoyannis in next week's chemistry in its element. Until then, I'm Meera Senthilingham and thank you for listening!

 

(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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In this experiment you will be looking at a group of transition elements chromium, molybdenum and tungsten.
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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.