|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|
|Phase||presumably a solid|
|Density (near r.t.)||23 (est.) g·cm−3|
|Crystal structure||cubic body centered|
|Oxidation states||3, 4|
|Ionization energies||1st: 580 kJ/mol|
|Atomic radius (calc.)||150 pm|
|Covalent radius||74 (calc.) pm|
|CAS registry number||53850-36-5|
Rutherfordium (pronounced /ˌrʌðɚˈfɔrdiəm/), also called eka-hafnium, is a chemical element in the periodic table that has the symbol Rf and atomic number 104. This is a highly radioactive synthetic element whose most stable isotope is 265Rf with a half-life of approximately 13 hours.
Rutherfordium was reportedly first synthesized in 1964 at the Joint Nuclear Research Institute at Dubna (U.S.S.R.). Researchers there bombarded 242Pu with accelerated 113 to 115 MeV 22Ne ions and claimed that they detected nuclear fission tracks in a special type of glass with a microscope which indicated the presence of a new element.
In 1969 researchers at the University of California, Berkeley synthesized the element by subjecting 249Cf and 12C to high energy collisions. The UC group also stated that they could not reproduce the earlier synthesis by Soviet scientists.
This resulted in an element naming controversy; since the Soviets claimed that it was first detected in Dubna, dubnium (Db) was suggested, as was kurchatovium (pronounced /ˌkɝtʃəˈtoʊviəm/, symbol Ku) for element 104, in honor of Igor Vasilevich Kurchatov (1903-1960), former head of Soviet nuclear research. The Americans, however, proposed rutherfordium (Rf) for the new element to honor Ernest Rutherford, who is known as the "father" of nuclear physics. The International Union of Pure and Applied Chemistry (IUPAC) adopted unnilquadium (/ˌjuːn
ɪlˈkwɒdiəm/, symbol Unq) as a temporary, systematic element name, derived from the Latin names for digits 1, 0, and 4. However in 1997 they resolved the dispute and adopted the current name. (Element 105 was named Dubnium, instead.)
- Michael Freemantle (2003). "Rutherfordium". Chemical & Engineering News.
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