Flerovium-289

Properties and data of the isotope ²⁸⁹Fl.

Content

Flerovium-289 is a radioisotope of the chemical element flerovium which, in addition to the element-specific 114 protons, has 175 neutrons in the atomic nucleus, resulting in the mass number 289. The very short-lived, only artificially producible, unstable and therefore radioactive nuclide has no practical significance; dealing with ²⁸⁹Fl is for academic purposes only.

General data

Name of the isotope:Flerovium-289; Fl-289Symbol:²⁸⁹Fl or 289114FlMass number A:289 (= number of nucleons)Atomic number Z:114 (= number of protons)Neutrons N:175Isotopic mass:289.19052(55) u (atomic weight of Flerovium-289)Nuclide mass:289.1279929 u (calculated nuclear mass without electrons)Mass excess:177.46824 MeVMass defect:2.217893948 u (per nucleus)Nuclear binding energy:2065.9549052 MeV (per nucleus)
7.14863289 MeV (average binding energy per nucleon)Separation energy:S_N = 5.523(918) MeV (first neutron)
S_P = 3.793(866) MeV (first proton)Half-life:2.4 sDecay constant λ:0.28881132523331 s^-1Specific activity α:6.018209282006 × 10⁺²⁰ Bq g^-1
16265430491.911 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2+Year of discovery:2004

Radioactive Decay

Half-life T_½ = 2.4 s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁸⁵Cn	> 94 %	9.954(65) MeV
SF	div	< 6 &

Occurrence

Comparison of the natural Flerovium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Flerovium Isotopic mixture	289.19042 u	100 %
Isotope ²⁸⁶Fl	286.18423(59) u	100 %	0.166 s	0+
Isotope ²⁸⁹Fl	289.19052(55) u	100 %	2.4 s	5/2+

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^289mFl

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 175) and isobaric (same nucleon number A = 289) with Flerovium-289. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.