Ununennium: Information from Answers.com

ununoctium ← ununennium → unbinilium

Fr
↑
Uue
↓
Uhe

119Uue

Periodic table

Appearance

General properties

ununennium, Uue, 119

1, 8, s

Standard atomic weight

unknown

Electron configuration

[Uuo] 8s¹ (predicted)

Electrons per shell

2, 8, 18, 32, 32, 18, 8, 1 (predicted) (Image)

Physical properties

Atomic properties

Ununennium (pronounced /ˌjuːnəˈnɛniəm/; officially, the two initial u's are to be pronounced /uː/ ( listen)^[1]), or eka-francium, is the temporary name of a hypothetical chemical element in the periodic table that has the temporary symbol Uue and has the atomic number 119. Since it is below the alkali metals it might have properties similar to those of francium or cesium. Like other alkali metals, it should be extremely reactive with water and air. A predicted oxidation state is 1.

Ununennium would be the first element in the eighth period of the periodic table and the seventh alkali metal.

1 Unsuccessful attempts at synthesis
2 Predicted decay characteristics
3 Target-projectile combinations leading to Z=119 compound nuclei
4 Theoretical calculations on evaporation cross sections
5 References
6 See also

Unsuccessful attempts at synthesis

The synthesis of element 119 was attempted in 1985 by bombarding a target of einsteinium-254 with calcium-48 ions at the superHILAC accelerator at Berkeley, California. No atoms were identified, leading to a limiting yield of 300 nb.^[2]

$\,^{254}_{99}\mathrm{Es} + \,^{48}_{20}\mathrm{Ca} \to \,^{302}_{119}\mathrm{Uue} ^{*} \to \ \ no\ atoms$

It is highly unlikely that this reaction will be useful given the extremely difficult task of making sufficient amounts of Es-254 to make a large enough target to increase the sensitivity of the experiment to the required level, due to the rarity of the element, and extreme rarity of the isotope.

Predicted decay characteristics

The alpha-decay half-lives of 1700 nuclei with 100 ≤ Z ≤ 130 have been calculated in a quantum tunneling model with alpha-decay Q-values from different mass estimates.^[3]^[4]^[5] The alpha-decay half-lives predicted for ^291-307119 are of the order of micro-seconds. The highest value of the alpha-decay half-life predicted in the quantum tunneling model with the mass estimates from a macroscopic-microscopic model is ~485 microseconds for the isotope ²⁹⁴119. For ³⁰²119 it is ~163 microseconds.

Target-projectile combinations leading to Z=119 compound nuclei

The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=119.

Target	Projectile	CN	Attempt result
²⁰⁸Pb	⁸⁷Rb	²⁹⁵119	Reaction yet to be attempted
²³²Th	⁶⁵Cu	²⁹⁷119	Reaction yet to be attempted
²³⁸U	⁵⁹Co	²⁹⁷119	Reaction yet to be attempted
²³⁷Np	⁵⁸Fe	²⁹⁵119	Reaction yet to be attempted
²⁴⁴Pu	⁵⁵Mn	²⁹⁹119	Reaction yet to be attempted
²⁴³Am	⁵⁴Cr	²⁹⁷119	Reaction yet to be attempted
²⁴⁸Cm	⁵¹V	²⁹⁹119	Reaction yet to be attempted
²⁴⁹Bk	⁵⁰Ti	²⁹⁹119	Reaction yet to be attempted
²⁴⁹Cf	⁴⁵Sc	²⁹⁴119	Reaction yet to be attempted
²⁵⁴Es	⁴⁸Ca	³⁰²119	Failure to date

Theoretical calculations on evaporation cross sections

The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

DNS = Di-nuclear system; σ = cross section

Target	Projectile	CN	Channel (product)	σ _max	Model	Ref
²⁵⁴Es	⁴⁸Ca	³⁰²119	3n (²⁹⁹119)	0.5 pb	DNS	^[6]

References

^ J. Chatt (1979). "Recommendations for the Naming of Elements of Atomic Numbers Greater than 100". Pure Appl. Chem. 51: 381–384. doi:10.1351/pac197951020381.
^ R. W. Lougheed, J. H. Landrum, E. K. Hulet, J. F. Wild, R. J. Dougan, A. D. Dougan, H. Gäggeler, M. Schädel, K. J. Moody, K. E. Gregorich, and G. T. Seaborg (1985). "Search for superheavy elements using ⁴⁸Ca + ²⁵⁴Es^g reaction". Physical Reviews C 32: 1760–1763. doi:10.1103/PhysRevC.32.1760. http://link.aps.org/abstract/PRC/v32/p1760.
^ C. Samanta, P. Roy Chowdhury and D.N. Basu (2007). "Predictions of alpha decay half lives of heavy and superheavy elements". Nucl. Phys. A 789: 142–154. doi:10.1016/j.nuclphysa.2007.04.001.
^ P. Roy Chowdhury, C. Samanta, and D. N. Basu (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Phys. Rev. C 77: 044603. doi:10.1103/PhysRevC.77.044603.
^ P. Roy Chowdhury, C. Samanta, and D. N. Basu (2008). "Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130". At. Data & Nucl. Data Tables 94: 781–806. doi:10.1016/j.adt.2008.01.003.
^ Feng, Z (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A 816: 33. doi:10.1016/j.nuclphysa.2008.11.003. http://arxiv.org/pdf/0803.1117.

Ununennium

Contents

Unsuccessful attempts at synthesis

Predicted decay characteristics

Target-projectile combinations leading to Z=119 compound nuclei

Theoretical calculations on evaporation cross sections

References

See also