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Name , symbol , atomic number Rutherfordium, Rf, 104
Element category Transition metals
Group , period , block 4 , 7 , d
Appearance unknown, probably silver-white or gray metallic
CAS number 53850-36-5
Mass fraction of the earth's envelope 0
Atomic mass 261,1087 u
Electron configuration [ Rn ] 5 f 14 6 d 2 7 s 2 (?)
1. Ionization energy 6th.02 (4) eV581 kJ / mol
2. Ionization energy 14th.35 (4) eV1 380 kJ / mol
3. Ionization energy 23.84 (4) eV2 300kJ / mol
4. Ionization energy 31.87 (4) eV3 070 kJ / mol
5. Ionization energy 64.0 (1.9) eV6 180 kJ / mol
Physical state presumably solid
density 17 g / cm 3
isotope NH t 1/2 ZA ZE (M eV ) ZP
253 Rf {syn.} 48 µs SF
254 Rf {syn.} 22.3 µs SF
255 Rf {syn.} 1.4 s α 251 No.
256 Rf {syn.} 6.2 ms α 252 no
257 Rf {syn.} 4.7 s α 252 no
ε 257 Lr
258 Rf {syn.} 13 ms SF
259 Rf {syn.} 3.1 s α 9.110 255 No.
260 Rf {syn.} 20 ms SF
261 Rf {syn.} 65 s α 8.110 257 no
262 Rf {syn.} 1.2 s SF
For other isotopes see list of isotopes
Hazard and safety information
GHS hazard labeling
no classification available
As far as possible and customary, SI units are used.
Unless otherwise noted, the data given apply to standard conditions .

Rutherfordium is an exclusively artificially produced chemical element with the element symbol Rf and the atomic number 104. It is one of the transactinoids . In the periodic table of the elements it is in the 4th  IUPAC group , the titanium group . All ten known isotopes of rutherfordium are radioactive .


Ernest Rutherford

The first synthesis of the element took place in 1964 by the Soviet researcher Georgi Fljorow at the nuclear research center near Dubna . There, plutonium was bombarded with neon nuclei :

It was named after Igor Kurchatov Kurchatovium (symbol Ku) in the Soviet Union and other countries . American researchers rejected the name for political reasons, claimed the first evidence of the element obtained in 1969 and suggested the name Rutherfordium (Rf), after Ernest Rutherford . Another suggestion was the name Dubnium (Db). (In addition: the 1967 discovery of element 105, also et al. By Georgi Fljorow, has been called Dubnium since 1997 - named after the nuclear research center near Dubna .)

The systematic name is Unnilquadium (Unq). It was not until 1997, six years after the end of the Soviet Union, that an agreement on rutherfordium was reached (see element naming controversy ).

The first syntheses confirmed later were carried out in 1968/69 by the American researchers Albert Ghiorso, Matti Nurmia, James Harris, Kari Eskola and Pirrko Eskola in Berkeley, USA with the help of the heavy ion accelerator HILAC:


Rutherfordium is one of the transition metals . It probably has the electron configuration [Rn] 5f 14 6d 2 7s 2 and thus has similar chemical properties to titanium , zirconium and hafnium ; with these it is counted to the titanium group. Due to the short disintegration time - the longest-lived isotope 261 only has a half-life of 65 seconds - and the small amounts available, the chemical properties have so far been of no importance. Presumably it forms slightly hydrated Rf 4+ ions in strong acid solutions and also complexes in hydrochloric acid , hydrobromic acid or hydrofluoric acid solutions.

safety instructions

There is no classification according to the CLP regulation or other regulations because only a few atoms of this element can be produced at the same time and thus far too few for a chemical or physical hazard.

Web links

Commons : Rutherfordium  - Collection of images, videos and audio files
Wiktionary: Rutherfordium  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. The values ​​for the properties (info box) are taken from (rutherfordium) , unless otherwise stated .
  2. a b c d e Entry on rutherfordium in Kramida, A., Ralchenko, Yu., Reader, J. and NIST ASD Team (2019): NIST Atomic Spectra Database (ver. 5.7.1) . Ed .: NIST , Gaithersburg, MD. doi : 10.18434 / T4W30F ( ). Retrieved June 13, 2020.
  3. a b c d e Entry on rutherfordium at WebElements, , accessed on June 13, 2020.
  4. The hazards emanating from radioactivity do not belong to the properties to be classified according to the GHS labeling. With regard to other hazards, this element has either not yet been classified or a reliable and citable source has not yet been found.
  5. ^ Harry H. Binder: Lexicon of the chemical elements , S. Hirzel Verlag, Stuttgart 1999, ISBN 3-7776-0736-3 .
  6. ^ A b R. C. Barber, NN Greenwood, AZ Hrynkiewicz, YP Jeannin, M. Lefort, M. Sakai, I. Ulehla, AP Wapstra, DH Wilkinson: Discovery of the transfermium elements. Part II: Introduction to discovery profiles. Part III: Discovery profiles of the transfermium elements (Note: For Part I see Pure Appl. Chem., Vol. 63, No. 6, pp. 879-886, 1991). In: Pure Appl. Chem. 65, 1993, pp. 1757-1814, doi : 10.1351 / pac199365081757 .
  7. GN Flerov, Yu.Ts. Oganesyan, Yu.V. Lobanov, VI Kuznetsov, VA Druin, VP Perelygin, KA Gavrilov, SP Tretiakova, VM Plotko: Synthesis and physical identification of the isotope of element 104 with mass number 260. In: Physics Letters. 13, 1964, pp. 73-75, doi : 10.1016 / 0031-9163 (64) 90313-0 .
  8. ^ Names and Symbols of Transfermium Elements (IUPAC Recommendations 1994). (PDF; 172 kB).
  9. ^ Names and Symbols of Transfermium Elements (IUPAC Recommendations 1997). (PDF; 167 kB).
  10. A. Ghiorso, M. Nurmia, J. Harris, K. Eskola, P. Eskola: Positive Identification of Two Alpha-Particle-Emitting Isotopes of Element 104. In: Physical Review Letters. 22, 1969, pp. 1317-1320, doi : 10.1103 / PhysRevLett.22.1317 .
  11. ^ JV Kratz: Critical evaluation of the chemical properties of the transactinide elements (IUPAC Technical Report) . In: Pure and Applied Chemistry . 75, No. 1, 2003, p. 103. doi : 10.1351 / pac200375010103 .