Francium-211

Properties and data of the isotope ²¹¹Fr.

Content

General data

Name of the isotope:Francium-211; Fr-211Symbol:²¹¹Fr or 21187FrMass number A:211 (= number of nucleons)Atomic number Z:87 (= number of protons)Neutrons N:124Isotopic mass:210.995555(13) u (atomic weight of Francium-211)Nuclide mass:210.9478344 u (calculated nuclear mass without electrons)Mass excess:-4.14049 MeVMass defect:1.759672368 u (per nucleus)Nuclear binding energy:1639.12425276 MeV (per nucleus)
7.76836139 MeV (average binding energy per nucleon)Separation energy:S_N = 8.878(19) MeV (first neutron)
S_P = 1.824(13) MeV (first proton)Half-life:3.10(2) minDecay constant λ:0.0037265977449459 s^-1Specific activity α:1.068671264208 × 10⁺¹⁹ Bq g^-1
288830071.40781 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2-Magnetic dipole moment:μ(μ_N) = + 4.00(8)Quadrupole moment Q:-0.19(3) barn (100 fm²)Nuclear g-factor:g_l = 0.88888888888889Charge radius:5.5882(176) femtometer fmYear of discovery:1964

Radioactive Decay

Half-life T_½ = 3.10(2) min (minutes) respectively 1.86 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁰⁷At	> 80 %	6.662(3) MeV
EE/β⁺	²¹¹Rn	< 20 %	4.615(14) MeV

Parent Nuclides

Direct parent isotope is: ²¹⁵Ac.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 124) and isobaric (same nucleon number A = 211) with Francium-211. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 124	Isobar A = 211
75	¹⁹⁹Re
76	²⁰⁰Os
77	²⁰¹Ir
78	²⁰²Pt
79	²⁰³Au
80	²⁰⁴Hg	²¹¹Hg
81	²⁰⁵Tl	²¹¹Tl
82	²⁰⁶Pb	²¹¹Pb
83	²⁰⁷Bi	²¹¹Bi
84	²⁰⁸Po	²¹¹Po
85	²⁰⁹At	²¹¹At
86	²¹⁰Rn	²¹¹Rn
87	²¹¹Fr	²¹¹Fr
88	²¹²Ra	²¹¹Ra
89	²¹³Ac	²¹¹Ac
90	²¹⁴Th	²¹¹Th
91	²¹⁵Pa
92	²¹⁶U