Rutherfordium

properties
[ Rn ] 5 f 14 6 d 2 7 s 2 (?) 104 para Periodic table
General
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
Atomic mass	261,1087 u
Electron configuration	[ Rn ] 5 f 14 6 d 2 7 s 2 (?)
1. Ionization energy	6th.02 (4) eV ≈ 581 kJ / mol
2. Ionization energy	14th.35 (4) eV ≈ 1 380 kJ / mol
3. Ionization energy	23.84 (4) eV ≈ 2 300kJ / mol
4. Ionization energy	31.87 (4) eV ≈ 3 070 kJ / mol
5. Ionization energy	64.0 (1.9) eV ≈ 6 180 kJ / mol
Physically
Physical state	presumably solid
density	17 g / cm 3
Isotopes
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. SF 256 Rf {syn.} 6.2 ms α 252 no SF 257 Rf {syn.} 4.7 s α 252 no ε 257 Lr SF 258 Rf {syn.} 13 ms SF 259 Rf {syn.} 3.1 s α 9.110 255 No. SF 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
Radioactive
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 .

history

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 :

${\displaystyle \mathrm {^{242}_{\ 94}Pu\ +\ _{10}^{22}Ne\ \longrightarrow \ \ _{104}^{260}Rf\ +\ 4\ _{0}^{1}n} }$

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:

${\displaystyle \mathrm {^{249}_{\ 98}Cf\ +\ _{\ 6}^{12}C\ \longrightarrow \ \ _{104}^{257}Rf\ +\ 4\ _{0}^{1}n} }$

${\displaystyle \mathrm {^{249}_{\ 98}Cf\ +\ _{\ 6}^{13}C\ \longrightarrow \ \ _{104}^{259}Rf\ +\ 3\ _{0}^{1}n} }$

${\displaystyle \mathrm {^{248}_{\ 96}Cm\ +\ _{\ 8}^{18}O\ \longrightarrow \ \ _{104}^{261}Rf\ +\ 5\ _{0}^{1}n} }$

properties

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 www.webelements.com (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 ( https://physics.nist.gov/asd ). Retrieved June 13, 2020.
3. ↑ ^{a b c d e} Entry on rutherfordium at WebElements, https://www.webelements.com , 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 .