Lawrencium

  • lawrencium, 103lr
    lawrencium
    pronunciationm/ (about this soundlisten) (ren-see-əm)
    appearancesilvery (predicted)[1]
    mass number[266]
    lawrencium in the periodic table
    hydrogen helium
    lithium beryllium boron carbon nitrogen oxygen fluorine neon
    sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
    potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
    caesium barium lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury (element) thallium lead bismuth polonium astatine radon
    francium radium actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
    lu

    lr

    (ups)
    nobeliumlawrenciumrutherfordium
    atomic number (z)103
    groupgroup n/a
    periodperiod 7
    blockf-block
    element category  actinide, sometimes considered a transition metal
    electron configuration[rn] 5f14 7s2 7p1
    electrons per shell2, 8, 18, 32, 32, 8, 3
    physical properties
    phase at stpsolid (predicted)
    melting point1900 k ​(1627 °c, ​2961 °f) (predicted)
    density (near r.t.)~15.6–16.6 g/cm3 (predicted)[2][3]
    atomic properties
    oxidation states+3
    electronegativitypauling scale: 1.3 (predicted)[4]
    ionization energies
    • 1st: 478.6 kj/mol[5]
    • 2nd: 1428.0 kj/mol (predicted)
    • 3rd: 2219.1 kj/mol (predicted)
    other properties
    natural occurrencesynthetic
    crystal structurehexagonal close-packed (hcp)
    hexagonal close-packed crystal structure for lawrencium

    (predicted)[6]
    cas number22537-19-5
    history
    namingafter ernest lawrence
    discoverylawrence berkeley national laboratory and joint institute for nuclear research (1961–1971)
    main isotopes of lawrencium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    254lr syn 13 s 78% α 250md
    22% ε 254no
    255lr syn 21.5 s α 251md
    256lr syn 27 s α 252md
    259lr syn 6.2 s 78% α 255md
    22% sf
    260lr syn 2.7 min α 256md
    261lr syn 44 min sf/ε?
    262lr syn 3.6 h ε 262no
    266lr syn 10 h sf
    | references

    lawrencium is a synthetic chemical element with the symbol lr (formerly lw) and atomic number 103. it is named in honor of ernest lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. a radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series. like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. thirteen isotopes of lawrencium are currently known; the most stable is 266lr with a half-life of 11 hours, but the shorter-lived 260lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale.

    chemistry experiments have confirmed that lawrencium behaves as a heavier homolog to lutetium in the periodic table, and is a trivalent element. it thus could also be classified as the first of the 7th-period transition metals: however, its electron configuration is anomalous for its position in the periodic table, having an s2p configuration instead of the s2d configuration of its homolog lutetium. this means that lawrencium may be more volatile than expected for its position in the periodic table and have a volatility comparable to that of lead.

    in the 1950s, 1960s, and 1970s, many claims of the synthesis of lawrencium of varying quality were made from laboratories in the soviet union and the united states. the priority of the discovery and therefore the naming of the element was disputed between soviet and american scientists, and while the international union of pure and applied chemistry (iupac) initially established lawrencium as the official name for the element and gave the american team credit for the discovery, this was reevaluated in 1997, giving both teams shared credit for the discovery but not changing the element's name.

  • history
  • characteristics
  • preparation and purification
  • see also
  • references
  • bibliography
  • external links

Lawrencium, 103Lr
Lawrencium
Pronunciationm/ (About this soundlisten) (REN-see-əm)
Appearancesilvery (predicted)[1]
Mass number[266]
Lawrencium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Lu

Lr

(Ups)
nobeliumlawrenciumrutherfordium
Atomic number (Z)103
Groupgroup n/a
Periodperiod 7
Blockf-block
Element category  Actinide, sometimes considered a transition metal
Electron configuration[Rn] 5f14 7s2 7p1
Electrons per shell2, 8, 18, 32, 32, 8, 3
Physical properties
Phase at STPsolid (predicted)
Melting point1900 K ​(1627 °C, ​2961 °F) (predicted)
Density (near r.t.)~15.6–16.6 g/cm3 (predicted)[2][3]
Atomic properties
Oxidation states+3
ElectronegativityPauling scale: 1.3 (predicted)[4]
Ionization energies
  • 1st: 478.6 kJ/mol[5]
  • 2nd: 1428.0 kJ/mol (predicted)
  • 3rd: 2219.1 kJ/mol (predicted)
Other properties
Natural occurrencesynthetic
Crystal structurehexagonal close-packed (hcp)
Hexagonal close-packed crystal structure for lawrencium

(predicted)[6]
CAS Number22537-19-5
History
Namingafter Ernest Lawrence
DiscoveryLawrence Berkeley National Laboratory and Joint Institute for Nuclear Research (1961–1971)
Main isotopes of lawrencium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
254Lr syn 13 s 78% α 250Md
22% ε 254No
255Lr syn 21.5 s α 251Md
256Lr syn 27 s α 252Md
259Lr syn 6.2 s 78% α 255Md
22% SF
260Lr syn 2.7 min α 256Md
261Lr syn 44 min SF/ε?
262Lr syn 3.6 h ε 262No
266Lr syn 10 h SF
| references

Lawrencium is a synthetic chemical element with the symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series. Like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Thirteen isotopes of lawrencium are currently known; the most stable is 266Lr with a half-life of 11 hours, but the shorter-lived 260Lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale.

Chemistry experiments have confirmed that lawrencium behaves as a heavier homolog to lutetium in the periodic table, and is a trivalent element. It thus could also be classified as the first of the 7th-period transition metals: however, its electron configuration is anomalous for its position in the periodic table, having an s2p configuration instead of the s2d configuration of its homolog lutetium. This means that lawrencium may be more volatile than expected for its position in the periodic table and have a volatility comparable to that of lead.

In the 1950s, 1960s, and 1970s, many claims of the synthesis of lawrencium of varying quality were made from laboratories in the Soviet Union and the United States. The priority of the discovery and therefore the naming of the element was disputed between Soviet and American scientists, and while the International Union of Pure and Applied Chemistry (IUPAC) initially established lawrencium as the official name for the element and gave the American team credit for the discovery, this was reevaluated in 1997, giving both teams shared credit for the discovery but not changing the element's name.