Francium-227

Properties and data of the isotope ²²⁷Fr.

Content

General data

Name of the isotope:Francium-227; Fr-227Symbol:²²⁷Fr or 22787FrMass number A:227 (= number of nucleons)Atomic number Z:87 (= number of protons)Neutrons N:140Isotopic mass:227.031865(6) u (atomic weight of Francium-227)Nuclide mass:226.9841444 u (calculated nuclear mass without electrons)Mass excess:29.68206 MeVMass defect:1.862001024 u (per nucleus)Nuclear binding energy:1734.44278185 MeV (per nucleus)
7.6407171 MeV (average binding energy per nucleon)Separation energy:S_N = 5.909(9) MeV (first neutron)
S_P = 6.354(12) MeV (first proton)Half-life:2.47(3) minDecay constant λ:0.0046771064815111 s^-1Specific activity α:1.240801499937 × 10⁺¹⁹ Bq g^-1
335351756.73989 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2+Magnetic dipole moment:μ(μ_N) = + 1.50(3)Nuclear g-factor:g_l = 3Charge radius:5.7335(179) femtometer fmYear of discovery:1972

Radioactive Decay

Half-life T_½ = 2.47(3) min (minutes) respectively 1.482 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²²⁷Ra	100 %	2.505(6) MeV

Parent Nuclides

Direct parent isotope is: ²²⁷Rn.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 140) and isobaric (same nucleon number A = 227) with Francium-227. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 140	Isobar A = 227
83	²²³Bi
84	²²⁴Po	²²⁷Po
85	²²⁵At	²²⁷At
86	²²⁶Rn	²²⁷Rn
87	²²⁷Fr	²²⁷Fr
88	²²⁸Ra	²²⁷Ra
89	²²⁹Ac	²²⁷Ac
90	²³⁰Th	²²⁷Th
91	²³¹Pa	²²⁷Pa
92	²³²U	²²⁷U
93	²³³Np	²²⁷Np
94	²³⁴Pu
95	²³⁵Am
96	²³⁶Cm
97	²³⁷Bk
98	²³⁸Cf