Bismuth-201

Properties and data of the isotope ²⁰¹Bi.

Content

General data

Name of the isotope:Bismuth-201; Bi-201Symbol:²⁰¹Bi or 20183BiMass number A:201 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:118Isotopic mass:200.977009(16) u (atomic weight of Bismuth-201)Nuclide mass:200.9314821 u (calculated nuclear mass without electrons)Mass excess:-21.41598 MeVMass defect:1.694928744 u (per nucleus)Nuclear binding energy:1578.81595546 MeV (per nucleus)
7.85480575 MeV (average binding energy per nucleon)Separation energy:S_N = 9.117(27) MeV (first neutron)
S_P = 2.454(19) MeV (first proton)Half-life:103(3) minDecay constant λ:0.00011215973795468 s^-1Specific activity α:3.377208703883 × 10⁺¹⁷ Bq g^-1
9127591.091577 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2-Magnetic dipole moment:μ(μ_N) = 4.8(3)Nuclear g-factor:g_l = 1.0666666666667Year of discovery:1950

Radioactive Decay

Half-life T_½ = 103(3) min (minutes) respectively 6.180 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	²⁰¹Pb	100 %	3.855(20) MeV

Parent Nuclides

Direct parent isotopes are: ²⁰⁵At, ²⁰¹Po.

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
^201mBi	846.35(18) keV	57.5(21) min	1/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 118) and isobaric (same nucleon number A = 201) with Bismuth-201. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 118	Isobar A = 201
72	¹⁹⁰Hf
73	¹⁹¹Ta
74	¹⁹²W
75	¹⁹³Re
76	¹⁹⁴Os	²⁰¹Os
77	¹⁹⁵Ir	²⁰¹Ir
78	¹⁹⁶Pt	²⁰¹Pt
79	¹⁹⁷Au	²⁰¹Au
80	¹⁹⁸Hg	²⁰¹Hg
81	¹⁹⁹Tl	²⁰¹Tl
82	²⁰⁰Pb	²⁰¹Pb
83	²⁰¹Bi	²⁰¹Bi
84	²⁰²Po	²⁰¹Po
85	²⁰³At	²⁰¹At
86	²⁰⁴Rn	²⁰¹Rn
87	²⁰⁵Fr	²⁰¹Fr
88	²⁰⁶Ra	²⁰¹Ra
89	²⁰⁷Ac
90	²⁰⁸Th