103 nobelium ← lawrencium → rutherfordium Lu ↑ Lr ↓ (Upt) Periodic Table - Extended Periodic Table
General
Name, Symbol, Number	lawrencium, Lr, 103
Chemical series	transition metals
Group, Period, Block	n/a, 7, d
Appearance	unknown, probably silvery white or metallic gray
Standard atomic weight	[262] g·mol−1
Electron configuration	[Rn] 5f14 6d1 7s2
Electrons per shell	2, 8, 18, 32, 32, 9, 2
Physical properties
Phase	presumably a solid
Melting point	- K (- °C, - °F)
Atomic properties
Oxidation states	3
Electronegativity	- (Pauling scale)
Ionization energies	1st: 443.8 kJ/mol
	2nd: 1428.0 kJ/mol
	3rd: 2219.1 kJ/mol
Miscellaneous
CAS registry number	22537-19-5
Selected isotopes
Main article: Isotopes of lawrencium iso NA half-life DM DE (MeV) DP 262Lr syn 3.6 h EC 262No 261Lr syn 44 m SF/EC? 260Lr syn 2.7 m alpha 8.04 256Md 259Lr syn 6.2 s 78% alpha 8.44 255Md 22% SF 258Lr syn 4.1 s alpha 8.68,8.65,8.62,8.59 254Md 257Lr syn 0.65 s alpha 8.86,8.80 253Md 256Lr syn 27 s alpha 8.62,8.52,8.32... 252Md 255Lr syn 21.5 s alpha 8.43,8.37 251Md 254Lr syn 13 s 78% alpha 8.46,8.41 250Md 22% EC 254No 253Lrm syn 0.57 s alpha 8.79 249Md 253Lrg syn 1.49 s 92% alpha 8.72 249Md 8% SF 252Lr syn 0.36 s alpha 9.02,8.97 248Md
References

Lawrencium (pronounced /ləˈrɛnsiəm/) is a radioactive synthetic element with the symbol Lr (formerly Lw) and atomic number 103. General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting... General Name, Symbol, Number rutherfordium, Rf, 104 Chemical series transition metals Group, Period, Block 4, 7, d Standard atomic weight (265) g·mol−1 Electron configuration probably [Rn] 5f14 6d2 7s2 Electrons per shell 2, 8, 18, 32, 32, 10, 2 Physical properties Phase presumably a solid Density (near r. ... General Name, Symbol, Number lutetium, Lu, 71 Chemical series lanthanides Group, Period, Block n/a, 6, d Appearance silvery white Standard atomic weight 174. ... Image File history File links Download high resolution version (890x260, 0 KB)stub for unified link coding, copy of File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... This is a standard display of the periodic table of the elements. ... An extended periodic table was suggested by Glenn T. Seaborg in 1969. ... This is a list of chemical elements, sorted by name and color coded according to type of element. ... A table of chemical elements ordered by atomic number and color coded according to type of element. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... A group, also known as a family, is a vertical column in the periodic table of the chemical elements. ... In the periodic table of the elements, a period is a horizontal row of the table. ... A block of the periodic table of elements is a set of adjacent groups. ... 6 *Lanthanides 7 **Actinides IUPAC has not recommended a specific format for the periodic table, so different conventions are permitted and are often used for the group number of lanthanides and actinides. ... A period 7 element is one of the chemical elements in the seventh row (or period) of the periodic table of the elements. ... D Block is a rap group based in Yonkers, New York. ... Color is an important part of the visual arts. ... The atomic mass (ma) is the mass of an atom at rest, most often expressed in unified atomic mass units. ... Electron atomic and molecular orbitals In atomic physics and quantum chemistry, the electron configuration is the arrangement of electrons in an atom, molecule, or other physical structure (, a crystal). ... For other uses, see Radon (disambiguation). ... For other uses, see Electron (disambiguation). ... Example of a sodium electron shell model An electron shell, also known as a main energy level, is a group of atomic orbitals with the same value of the principal quantum number n. ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... This box:      For other uses, see Solid (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ... For other uses, see Kelvin (disambiguation). ... For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ... In chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. ... Electronegativity is a measure of the ability of an atom or molecule to attract electrons in the context of a chemical bond. ... The ionization energy (IE) of an atom or of a molecule is the energy required to strip it of an electron. ... Kilojoule per mole are an SI derived unit of energy per amount of material, where energy is measured in units of 1000 joules, and the amount of material is measured in mole units. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... Lawrencium (Lr) has no stable isotopes. ... For other uses, see Isotope (disambiguation). ... Natural abundance refers to the prevalence of different isotopes of an element as found in nature. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... In physics, the decay mode describes a particular way a particle decays. ... The decay energy is the energy released by a nuclear decay. ... The electronvolt (symbol eV) is a unit of energy. ... In nuclear physics, a decay product, also known as a daughter product, is a nuclide resulting from the radioactive decay of a parent or precursor nuclide. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... A Synthetic radioisotope is a radionuclide that is not found in nature: no natural process or mechanism exists which produces it, or it is so unstable that it decays away in a very short period of time. ... Recommended values for many properties of the elements, together with various references, are collected on these data pages. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ... The chemical elements labelled as synthetic are unstable, with a half-life so short (ranging from a fraction of millisecond to a few million years) relative to the age of the Earth that any atoms of that element that may have been present when the Earth formed have long since... See also: List of elements by atomic number In chemistry and physics, the atomic number (also known as the proton number) is the number of protons found in the nucleus of an atom. ...

Lawrencium

Common English pronunciation of lawrencium

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Its most stable isotope is ²⁶²Lr, with a half-life of approximately 3.6 hours. Little is known of the chemistry but there is strong evidence for the formation of a trivalent ion in aqueous solution, confirming lawrencium's place as the last member of the actinoids. Although lawrencium is often placed as the last member of the 5f-block, it can also be regarded as the first member of the 6d-block (see extended periodic table). Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... The hour (symbol: h) is a unit of time. ... The actinide series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table with atomic numbers 89 - 103. ... This extended periodic table was suggested by Glenn T. Seaborg in 1969. ...

Official discovery

Lawrencium was reported by Albert Ghiorso, Torbjørn Sikkeland, Almon Larsh, and Robert M. Latimer on February 14, 1961 at the Lawrence Radiation Laboratory (now called Lawrence Berkeley National Laboratory) on the University of California, Berkeley campus. It was produced by bombarding a three milligram target composed of three isotopes of californium with boron-10 and B-11 ions in the Heavy Ion Linear Accelerator (HILAC). This article or section should be merged with Timeline of chemical element discovery The story of the discoveries of the chemical elements is presented here in chronological order. ... Albert Ghiorso (b. ... is the 45th day of the year in the Gregorian calendar. ... Year 1961 (MCMLXI) was a common year starting on Sunday (link will display full calendar) of the Gregorian calendar. ... The Ernest Orlando Lawrence Berkeley National Laboratory (LBNL), formerly the Berkeley Radiation Laboratory and usually shortened to Berkeley Lab or LBL, is a U.S. Department of Energy (DOE) national laboratory conducting unclassified scientific research. ... Sather tower (the Campanile) looking out over the San Francisco Bay and Mount Tamalpais. ... The milligram (symbol mg) is an SI unit of mass. ... General Name, Symbol, Number californium, Cf, 98 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (251) g·mol−1 Electron configuration [Rn] 5f10 7s2 Electrons per shell 2, 8, 18, 32, 28, 8, 2 Physical properties Phase solid... For other uses, see Boron (disambiguation). ...

The Berkeley team reported that the isotope ²⁵⁷103 was detected in this manner and decayed by emitting an 8.6 MeV alpha particle with a half-life of ~8 seconds. The assignment was later corrected to ²⁵⁸Lr. For other uses, see Isotope (disambiguation). ... An alpha particle is deflected by a magnetic field Alpha radiation consists of helium-4 nuclei and is readily stopped by a sheet of paper. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

The team suggested the name lawrencium (Lw) for the new element.

In 1967, researchers in Dubna, Russia reported that they were not able to confirm an alpha emitter with a half-life of 8 seconds as ²⁵⁷103. This assignment has since been changed to ²⁵⁸Lr. Instead, they reported a 45s activity assigned to ²⁵⁶Lr. Year 1967 (MCMLXVII) was a common year starting on Sunday (link will display full calendar) of the 1967 Gregorian calendar. ... Dubna is a small city located in central Russia, in the Taldomsky district of Moscow Oblast, approximately 125 km north of Moscow, on the banks of the Volga river. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

Further work in 1969 indicated an actinoid chemistry for the new element. The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ...

In 1971, the team at the University of California performed a whole series of experiments aimed at measuring the decay properties of lawrencium isotopes with mass numbers from 255-260.

In 1992, The IUPAC/IUPAP Transfermium Working Group (TWG) officially recognised the Dubna and Berkeley teams as co-discovers of lawrencium. The International Union of Pure and Applied Chemistry (IUPAC) is an international non-governmental organization devoted to the advancement of chemistry. ...

Naming

The origin of the name, preferred by the American Chemical Society, is in reference to Ernest O. Lawrence, inventor of the cyclotron. The symbol Lw originally was used but in 1963 it was changed to Lr. In August 1997 the International Union of Pure and Applied Chemistry (IUPAC) ratified the name lawrencium and symbol Lr during a meeting in Geneva. Unniltrium (IPA: /juːˈnɪltriəm/, symbol Unt) was sometimes used as a temporary, systematic element name until that time. Lawrencium also has been called eka-lutetium.^[1] The American Chemical Society (ACS) is a learned society (professional association) based in the United States that supports scientific inquiry in the field of chemistry. ... Ernest Orlando Lawrence (August 8, 1901 - August 27, 1958) was an American physicist and Nobel laureate best known for his invention of the cyclotron. ... A pair of Dee electrodes with loops of coolant pipes on their surface at the Lawrence Hall of Science. ... For other uses, see 1963 (disambiguation). ... For the band, see 1997 (band). ... IUPAC logo The International Union of Pure and Applied Chemistry (IUPAC) (Pronounced as eye-you-pack) is an international non-governmental organization established in 1919 devoted to the advancement of chemistry. ... Geneva (pronunciation //; French: Genève //, German:   //, Italian: Ginevra //, Romansh: Genevra) is the second most populous city in Switzerland (after Zürich), and is the most populous city of Romandy (the French-speaking part of Switzerland). ... In chemistry, heavy transuranic elements receive a permanent trivial name and symbol only after their synthesis has been confirmed. ... Professor Dimitri Mendeleev published the first Periodic Table of the Atomic Elements in 1869 based on properties which appeared with some regularity as he laid out the elements from lightest to heaviest. ... General Name, Symbol, Number lutetium, Lu, 71 Chemical series lanthanides Group, Period, Block n/a, 6, d Appearance silvery white Standard atomic weight 174. ...

Electronic structure

Lawrencium is element 103 in the Periodic Table. The two forms of the projected electronic structure are:

Bohr model: 2, 8, 18, 32, 32, 9, 2

Quantum mechanical model: 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰ 4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰ 6p⁶7s²5f¹⁴6d¹

There has been a suggestion that the electron configuration could be 7s²5f¹⁴7p¹ but experiments to examine this have been not possible to date.

Physical characteristics

The appearance of this element is unknown, however it is most likely silvery-white or gray and metallic. If sufficient amounts of lawrencium were produced, it would pose a radiation hazard. Contrary to some sources, bulk properties of this element, such as the melting point, have not been possible to measure to date. However, the 1^st, 2^nd and 3^rd ionization energies have been measured. This article is about metallic materials. ... Radiation hazard symbol. ...

Periodic classification

A strict correlation between periodic table blocks and electron configuration for neutral atoms would describe lawrencium as a transition metal because it should be classed as a d-block element. However, it is classified as an actinoid according to IUPAC recommendations.^[2] A block of the periodic table of elements is a set of adjacent groups. ... In chemistry, the term transition metal (sometimes also called a transition element) has two possible meanings: It commonly refers to any element in the d-block of the periodic table, including zinc, cadmium and mercury. ... D Block is a rap group based in Yonkers, New York. ... The actinide series encompasses the 14 chemical elements that lie between actinium and nobelium on the periodic table with atomic numbers 89 - 102 inclusive. ... The International Union of Pure and Applied Chemistry (IUPAC) is an international non-governmental organization devoted to the advancement of chemistry. ...

Experimental chemistry

Gas phase chemistry

The first gas phase studies were reported in 1969 by a team at the Flerov Laboratory of Nuclear Reactions (FLNR). They used the reaction ²⁴³Am+¹⁸O to produce lawrencium nuclei which reacted with a stream of chlorine gas to form a volatile chloride component. The product was assigned to ²⁵⁶LrCl₃ and confirmed that lawrencium was a typical actinide. General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series derives its name from the first element in the series, actinium. ...

Aqueous phase chemistry

The first liquid phase studies were reported in 1970 by the team at the LBNL. They used the reaction ²⁴⁹Cf+¹¹B to produce lawrencium nuclei. They were able to show that lawrencium formed a trivalent ion, similar to other actinides but in stark contrast to nobelium. Further work in 1988 confirmed the formation of a trivalent lawrencium(III) ion using anion-exchange chromatography using α-hydroxyisobutyrate (α-HIB) complex. Comparison of the elution time with other actinides allowed a determination of 88.6 pm for the ionic radius for Lr³⁺. Attempts to reduce Lr(III) to Lr(I) using the potent reducing agent hydroxylamine hydrochloride were unsuccessful. This article is about the electrically charged particle. ... The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series derives its name from the first element in the series, actinium. ... General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting...

Summary of compounds and complex ions

Isotopes

Main article: Isotopes of lawrencium

Twelve isotopes of lawrencium have been synthesized with ²⁶²Lr being the longest-lived and heaviest, with a half-life of 216 minutes. ²⁵²Lr is the lightest isotope known to date. Lawrencium (Lr) has no stable isotopes. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

History of synthesis of isotopes by cold fusion

²⁰⁵Tl(⁵⁰Ti,xn)^255-xLr (x=2?)

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. Evidence was provided for the formation of ²⁵³Lr in the 2n exit channel.

²⁰³Tl(⁵⁰Ti,xn)^253-xLr

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR.

²⁰⁸Pb(⁴⁸Ti,pxn)^255-xLr (x=1?)

This reaction was reported in 1984 by Yuri Oganessian at the FLNR. The team was able to detect decays of ²⁴⁶Cf, a descendant of ²⁵⁴Lr.

²⁰⁸Pb(⁴⁵Sc,xn)^253-xLr

This reaction was studied in a series of experiments in 1976 by Yuri Oganessian and his team at the FLNR. Results are not readily available.

²⁰⁹Bi(⁴⁸Ca,xn)^257-xLr (x=2)

This reaction has been used to study the spectroscopic properties of ²⁵⁵Lr. The team at GANIL used the reaction in 2003 and the team at the FLNR used it between 2004-2006 to provide further information for the decay scheme of ²⁵⁵Lr. The work provided evidence for an isomeric level in ²⁵⁵Lr.

History of synthesis of isotopes by hot fusion

²⁴³Am(¹⁸O,xn)^261-xLr (x=5)

This reaction was first studied in 1965 by the team at the FLNR. They were able to detect a 45s activity assigned to ²⁵⁶Lr or ²⁵⁷Lr. Later work suggests an assignment to ²⁵⁶Lr. Further studies in 1968 produced an 8.35-8.60 MeV alpha activity with a half-life of 35s. This activity was also initially assigned to ²⁵⁶Lr or ²⁵⁷Lr and later to solely ²⁵⁶Lr. Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

²⁴³Am(¹⁶O,xn)^259-xLr (x=4)

This reaction was studied in 1970 by the team at the FLNR. They were able to detect an 8.38 MeV alpha activity with a half-life of 20s. This was assigned to ²⁵⁵Lr. Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

²⁴⁸Cm(¹⁵N,xn)^263-xLr (x=3,4,5)

This reaction was studied in 1971 by the team at the LBNL in their large study of lawrencium isotopes. They were able to assign alpha activities to ²⁶⁰Lr,²⁵⁹Lr and ²⁵⁸Lr from the 3-5n exit channels.

²⁴⁸Cm(¹⁸O,pxn)^265-xLr (x=3,4)

This reaction was studied in 1988 at the LBNL in order to assess the possibility of producing ²⁶²Lr and ²⁶¹Lr without using the exotic ²⁵⁴Es target. It was also used to attempt to measure an EC branch in ^261mRf from the 5n exit channel. After extraction of the Lr(III) component, they were able to measure the spontaneous fission of ²⁶¹Lr with an improved half-life of 44 minutes. The production cross-section was 700 pb. On this basis, a 14% EC branch was calculated if this isotope was produced via the 5n channel rather than the p4n channel. A lower bombarding energy (93 MeV c.f. 97 MeV) was then used to measure the production of ²⁶²Lr in the p3n channel. The isotope was successfully detected and a yield of 240 pb was measured. The yield was lower than expected compared to the p4n channel. However, the results were judged to indicate that the 261Lr was most likely produced by a p3n channel and an upper limit of 14% for the EC branch of ^261mRf was therefore suggested. Spontaneous fission (SF) is a form of radioactive decay characteristic of very heavy isotopes, and is theoretically possible for any atomic nucleus whose mass is greater than or equal to 100 amu (elements near ruthenium). ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

²⁴⁶Cm(¹⁴N,xn)^260-xLr (x=3?)

This reaction was studied briefly in 1958 at the LBNL using an enriched ²⁴⁴Cm target (5% ²⁴⁶Cm). They observed a ~9 MeV alpha activity with a half-life of ~0.25 seconds. Later results suggest a tentative assignment to ²⁵⁷Lr from the 3n channel Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

²⁴⁴Cm(¹⁴N,xn)^258-xLr

This reaction was studied briefly in 1958 at the LBNL using an enriched ²⁴⁴Cm target (5% ²⁴⁶Cm). They observed a ~9 MeV alpha activity with a half-life of ~0.25s. Later results suggest a tentative assignment to ²⁵⁷Lr from the 3n channel with the ²⁴⁶Cm component. No activities assigned to reaction with the ²⁴⁴Cm component have been reported. Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

²⁴⁹Bk(¹⁸O,αxn)^263-xLr (x=3)

This reaction was studied in 1971 by the team at the LBNL in their large study of lawrencium isotopes. They were able to detect an activity assigned to ²⁶⁰Lr. The reaction was further studied in 1988 to study the aqueous chemistry of lawrencium. A total of 23 alpha decays were measured for ²⁶⁰Lr, with a mean energy of 8.03 MeV and an improved half-life of 2.7 minutes. The calculated cross-section was 8.7 nb. Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

²⁵²Cf(¹¹B,xn)^263-xLr (x=5,7??)

This reaction was first studied in 1961 at the University of California by Albert Ghiorso by using a californium target (52% ²⁵²Cf). They observed three alpha activities of 8.6 MeV, 8.4 MeV and 8.2 MeV, with half-lives of ~8s and 15s, respectively. The 8.6 MeV activity was tentatively assigned to ²⁵⁷Lr. Later results suggest a reassignment to ²⁵⁸Lr, resulting from the 5n exit channel. The 8.4 MeV activity was also assigned to ²⁵⁷Lr. Later results suggest a reassignment to ²⁵⁶Lr. This is most likely from the 33% ²⁵⁰Cf component in the target rather than from the 7n channel. The 8.2 MeV was subsequently associated with nobelium. Albert Ghiorso (b. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting...

²⁵²Cf(¹⁰B,xn)^262-xLr (x=4,6)

This reaction was first studied in 1961 at the University of California by Albert Ghiorso by using a californium target (52% ²⁵²Cf). They observed three alpha activities of 8.6 MeV, 8.4 MeV and 8.2 MeV, with half-lives of ~8s and 15s, respectively. The 8.6 MeV activity was tentatively assigned to ²⁵⁷Lr. Later results suggest a reassignment to ²⁵⁸Lr. The 8.4 MeV activity was also assigned to ²⁵⁷Lr. Later results suggest a reassignment to ²⁵⁶Lr. The 8.2 MeV was subsequently associated with nobelium. Albert Ghiorso (b. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting...

²⁵⁰Cf(¹⁴N,αxn)^260-xLr (x=3)

This reaction was studied in 1971 at the LBNL. They were able to identify a 0.7s alpha activity with two alpha lines at 8.87 and 8.82 MeV. This was assigned to ²⁵⁷Lr.

²⁴⁹Cf(¹¹B,xn)^260-xLr (x=4)

This reaction was first studied in 1970 at the LBNL in an attempt to study the aqueous chemistry of lawrencium. They were able to measure a Lr³⁺ activity. The reaction was repeated in 1976 at Oak Ridge and 26s ²⁵⁶Lr was confirmed by measurement of coincident X-rays.

²⁴⁹Cf(¹²C,pxn)^260-xLr (x=2)

This reaction was studied in 1971 by the team at the LBNL. They were able to detect an activity assigned to ²⁵⁸Lr from the p2n channel.

²⁴⁹Cf(¹⁵N,αxn)^260-xLr (x=2,3)

This reaction was studied in 1971 by the team at the LBNL. They were able to detect an activities assigned to ²⁵⁸Lr and ²⁵⁷Lr from the α2n and α3n and channels. The reaction was repeated in 1976 at Oak Ridge and the synthesis of ²⁵⁸Lr was confirmed.

²⁵⁴Es + ²²Ne - transfer

This reaction was studied in 1987 at the LLNL. They were able to detect new SF activities assigned to ²⁶¹Lr and ²⁶²Lr, resulting from transfer from the ²²Ne nuclei to the ²⁵⁴Es target. In addition, a 5 ms SF activity was detected in delayed coincidence with nobelium K X-rays and was assigned to ²⁶²No, resulting from the EC of ²⁶²Lr. General Name, Symbol, Number nobelium, No, 102 Chemical series actinides Group, Period, Block n/a, 7, f Appearance unknown, probably silvery white or metallic gray Atomic mass (259) g/mol Electron configuration [Rn] 5f14 7s2 Electrons per shell 2, 8, 18, 32, 32, 8, 2 Physical properties Phase solid Melting...

Synthesis of isotopes as decay products

Isotopes of lawrencium have also been identified in the decay of heavier elements. Observations to date are summarised in the table below:

Chronology of isotope discovery

Isomerism in lawrencium nuclides

²⁵⁵Lr

Recent work on the spectroscopy of ²⁵⁵Lr formed in the reaction ²⁰⁹Bi(⁴⁸Ca,2n)²⁵⁵Lr has provided evidence for an isomeric level.

²⁵³Lr

A study of the decay properties of ²⁵⁷Db (see dubnium) in 2001 by Hessberger et al. at the GSI provided some data for the decay of ²⁵³Lr. Analysis of the data indicated the population of two isomeric levels in ²⁵³Lr from the decay of the corresponding isomers in ²⁵⁷Db. The ground state was assigned spin and parity of 7/2-, decaying by emission of an 8794 KeV alpha particle with a half-life of 0.57s. The isomeric level was assigned spin and parity of 1/2-, decaying by emission of an 8722 KeV alpha particle with a half-life of 1.49s. General Name, Symbol, Number dubnium, Db, 105 Chemical series transition metals Group, Period, Block 5, 7, d Appearance unknown, probably silvery white or metallic gray Atomic mass (262) g/mol Electron configuration perhaps [Rn] 5f14 6d3 7s2 (guess based on tantalum) Electrons per shell 2, 8, 18, 32, 32, 11... The terms spin and SPIN have several meanings, including those primarily discussed as spinning: For spin in sub-atomic physics, see spin (physics) For the stalled aircraft maneuver or any of several forms of loss of control in aircraft, see spin (flight) For the periodical, see Spin Magazine For the... Look up Parity in Wiktionary, the free dictionary Parity is a concept of equality of status or functional equivalence. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ... The terms spin and SPIN have several meanings, including those primarily discussed as spinning: For spin in sub-atomic physics, see spin (physics) For the stalled aircraft maneuver or any of several forms of loss of control in aircraft, see spin (flight) For the periodical, see Spin Magazine For the... Look up Parity in Wiktionary, the free dictionary Parity is a concept of equality of status or functional equivalence. ... Half-Life For a quantity subject to exponential decay, the half-life is the time required for the quantity to fall to half of its initial value. ...

Chemical yields of isotopes

Cold fusion

The table below provides cross-sections and excitation energies for cold fusion reactions producing rutherfordium isotopes directly. Data in bold represents maxima derived from excitation function measurements. + represents an observed exit channel.

References

1. ^ Glenn T. Seaborg (1951-12-12). The transuranium elements: present status (Nobel Lecture).
2. ^ IUPAC "Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004)"

Notes

• Los Alamos National Laboratory's Chemistry Division: Periodic Table - Lawrencium
• Guide to the Elements - Revised Edition, Albert Stwertka, (Oxford University Press; 1998) ISBN 0-19-508083-1

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