2007 Schools Wikipedia Selection. Related subjects: Chemical elements

104 lawrenciumrutherfordiumdubnium


Periodic Table - Extended Periodic Table
Name, Symbol, Number rutherfordium, Rf, 104
Chemical series transition metals
Group, Period, Block 4, 7, d
Appearance unknown, probably silvery
white or metallic gray
Atomic mass (265) g/mol
Electron configuration probably [Rn] 5f14 6d2 7s2
Electrons per shell 2, 8, 18, 32, 32, 10, 2
Phase presumably a solid
Ionization energies 1st: 580 kJ/mol
CAS registry number 53850-36-5

Rutherfordium ( IPA: /ˌrʌðə(r)ˈfɔːdiəm/), 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.

This element therefore has no applications and little is known about it. Rutherfordium is the first transactinide element and it is predicted to have chemical properties similar to hafnium.


Rutherfordium (named in honour of noted New Zealand nuclear physicist Ernest Rutherford) 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 ( IPA: /ˌkəːtʃəˈtəʊviəm/, symbol Ku) for element 104, in honour of Igor Vasilevich Kurchatov ( 1903- 1960), former head of Soviet nuclear research. The Americans, however, proposed rutherfordium (Rf) for the new element to honour Ernest Rutherford, who is known as the "father" of nuclear physics. The International Union of Pure and Applied Chemistry ( IUPAC) adopted unnilquadium ( IPA: /ˌjuːnɪlˈkwɒdiəm/, 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.)

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