The chemical element lawrencium is classed as an actinide metal. It was discovered in 1961 by Albert Ghiorso, Torbjørn Sikkeland, Almon Larsh and Robert Latimer.
|Classification:||Lawrencium is an actinide metal|
|Atomic weight:||(262), no stable isotopes|
|Neutrons in most abundant isotope:||159|
|Electron configuration:||[Rn] 5f14 6d1 7s2|
|Density @ 20oC:|
|Specific heat capacity||–|
|Heat of fusion||–|
|Heat of atomization||–|
|Heat of vaporization||–|
|1st ionization energy||470 kJ mol-1|
|2nd ionization energy||–|
|3rd ionization energy||–|
|Minimum oxidation number||0|
|Min. common oxidation no.||0|
|Maximum oxidation number||3|
|Max. common oxidation no.||3|
|Electronegativity (Pauling Scale)||–|
|Reaction with air|
|Reaction with 15 M HNO3|
|Reaction with 6 M HCl|
|Reaction with 6 M NaOH|
|Ionic radius (1+ ion)||–|
|Ionic radius (2+ ion)||88.6 pm|
|Ionic radius (3+ ion)||–|
|Ionic radius (1- ion)||–|
|Ionic radius (2- ion)||–|
|Ionic radius (3- ion)||–|
Discovery of Lawrencium
Lawrencium was synthesized in 1961 by Albert Ghiorso, Torbjørn Sikkeland, Almon Larsh and Robert Latimer at the Lawrence Berkeley National Laboratory, California. It was the last member of the actinide series to be discovered.
A heavy-ion linear accelerator (HILAC) was used to bombard a 3 milligram target of californium (consisting of a mixture of californium isotopes of mass number 249, 250, 251, and 252) with boron-10 and boron-11 ions, producing lawrencium. (1), (2)
The target consisted of a mixture of californium isotopes and therefore an exact mass of the new element could not be assigned. Later research suggested that lawrencium-258 (half-life 4.2 seconds) was produced in the 1961 experiment. (2)
The element was named after Ernest Lawrence, inventor of the cyclotron particle accelerator.
The symbol Lw was used originally, but in 1963 this was changed by The International Union of Pure and Applied Chemistry (IUPAC) to Lr.
Appearance and Characteristics
Lawrencium is harmful due to its radioactivity.
Lawrencium is a synthetic, highly radioactive metal that has only been produced in miniscule amounts.
Lawrencium is a trivalent ion in aqueous solution. (2a)
Lawrencium metal has not been prepared. (2b)
All of its isotopes are short-lived. Its longest lived isotopes is 262Lr with a half-life of 216 minutes.
Uses of Lawrencium
Lawrencium is of scientific research interest only.
Abundance and Isotopes
Abundance earth’s crust: nil
Abundance solar system: –
Cost, pure: $ per g
Cost, bulk: per 100g
Source: Lawrencium is a synthetic element and is not found naturally. Lawrencium is created by nuclear bombardment, and has only been produced in miniscule amounts. Lawrencium-256 can be produced by the irradiation of a californium-249 target with boron-11 ions. Lawrencium-260 can be produced by the irradiation of a berkelium-249 target with oxygen-18 ions. (2c)
Isotopes: Lawrencium has 10 isotopes whose half-lives are known, with mass numbers 253 to 262. Lawrencium has no naturally occurring isotopes. Its longest lived isotopes are 262Lr with a half-life of 216 minutes, 261Lr, with a half-life of 39 minutes and 260Lr with a half-life of 180 seconds.
1. John Emsley, Nature’s building blocks: an A-Z guide to the elements., Oxford University Press, 2003., p460.
2. Robert J. Silva, The Chemistry of the Actinide and Transactinide Elements., Springer., Vol 3.13, p1641-p1642.
2a. Robert J. Silva, The Chemistry of the Actinide and Transactinide Elements., Springer., Vol 3.13, 1645.
2b. Robert J. Silva, The Chemistry of the Actinide and Transactinide Elements., Springer., Vol 3.13, p1644.
2c. Robert J. Silva, The Chemistry of the Actinide and Transactinide Elements., Springer., Vol 3.13, p1642.
3. Image LBL.
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