Francium-213

Properties and data of the isotope ²¹³Fr.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Francium-213 is a radioisotope of the chemical element francium, which has 126 neutrons in its atomic nucleus in addition to the element-specific 87 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 213. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ²¹³Fr is exclusively for academic purposes and experimental research.

In 1964, a report was published describing the isotope francium-213 for the first time. In the experiments described therein, 86 MeV carbon-12 ions reacted with a thallium-205 template, producing the nuclide in the reaction

²⁰⁵Tl(¹²C,4n)²¹³Fr [1].

See also: List of individual Francium isotopes (and general data sources).

General data

Name of the isotope:Francium-213; Fr-213Symbol:²¹³Fr or 21387FrMass number A:213 (= number of nucleons)Atomic number Z:87 (= number of protons)Neutrons N:126Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.448275862069 (= neutron-proton ratio)Neutron excess (N-Z):39Isotopic mass:212.996184(5) u (atomic weight of Francium-213)Nuclide mass:212.9484634 u (calculated nuclear mass without electrons)Mass excess:-3.55458 MeVMass defect:1.7763732 u (per nucleus)Nuclear binding energy:1654.68097756 MeV (per nucleus)
7.76845529 MeV (average binding energy per nucleon)Separation energy:S_N = 8.110(10) MeV (first neutron)
S_P = 2.184(6) MeV (first proton)Half-life:34.17(6) sDecay constant λ:0.020285255503657 s^-1Specific activity α:5.762295567114 × 10⁺¹⁹ Bq g^-1
1557377180.3012 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2-Magnetic dipole moment:μ(μ_N) = +4.02(8)Quadrupole moment Q:- 0.14(2) barn (100 fm²)Nuclear g-factor:g_l = 0.89333333333333Charge radius:5.5977(176) femtometer fmYear of discovery:1964

Radioactive Decay

Half-life T_½ = 34.17(6) s respectively 3.417 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁰⁹At	99.44(5) %	6.9047(13) MeV
EC/β⁺	²¹³Rn	0.56(5) %	2.142(6) MeV

Parent Nuclides

Direct parent isotopes are: ²¹⁷Ac, ²¹³Ra.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 126) and isobaric (same nucleon number A = 213) with Francium-213. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 126	Isobar A = 213
76	²⁰²Os
77	²⁰³Ir
78	²⁰⁴Pt
79	²⁰⁵Au
80	²⁰⁶Hg	²¹³Hg
81	²⁰⁷Tl	²¹³Tl
82	²⁰⁸Pb	²¹³Pb
83	²⁰⁹Bi	²¹³Bi
84	²¹⁰Po	²¹³Po
85	²¹¹At	²¹³At
86	²¹²Rn	²¹³Rn
87	²¹³Fr	²¹³Fr
88	²¹⁴Ra	²¹³Ra
89	²¹⁵Ac	²¹³Ac
90	²¹⁶Th	²¹³Th
91	²¹⁷Pa	²¹³Pa
92	²¹⁸U
93	²¹⁹Np

External data and identifiers

Adopted Levels, Gammas:NuDat 213Fr

Literature and References

[1] - Roger D. Griffioen, Ronald D. Macfarlane:
Alpha-Decay Properties of Some Francium Isotopes Near the 126-Neutron Closed Shell.
In: Physical Review, (1964), DOI 10.1103/PhysRev.133.B1373.

[2] - M. Fisichella et al.:
Determination of the half-life of ²¹³Fr with high precision.
In: Physical Review C, 88, 011303(R), (2013), DOI 10.1103/PhysRevC.88.011303.

[3] - C. Clisu et al.:
Observation of the J ≤ 7/2 low-spin states in ²¹³Fr populated in the electron capture of the 1/2^- ground state of ²¹³Ra.
In: Physical Review C, 110, 064315, (2024), DOI 10.1103/PhysRevC.110.064315.