Bismuth-212

Properties and data of the isotope ²¹²Bi.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Bismuth-212 is the radioisotope of the element Bismuth, whose atomic nucleus has 129 neutrons in addition to the element-specific 83 protons, resulting in a mass number of 212.

The discovery of the radioactive nuclide during the investigation of the decay products of radon-220 was reported in 1905 [1].

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

General data

Name of the isotope:Bismuth-212; Bi-212Other names:Thorium CSymbol:²¹²Bi or 21283BiMass number A:212 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:129Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.5542168674699 (= neutron-proton ratio)Neutron excess (N-Z):46Isotopic mass:211.991285(2) u (atomic weight of Bismuth-212)Nuclide mass:211.9457581 u (calculated nuclear mass without electrons)Mass excess:-8.11797 MeVMass defect:1.77596682 u (per nucleus)Nuclear binding energy:1654.30243703 MeV (per nucleus)
7.80331338 MeV (average binding energy per nucleon)Separation energy:S_N = 4.330(6) MeV (first neutron)
S_P = 4.9139(27) MeV (first proton)Half-life:60.55(6) minDecay constant λ:0.00019079195721441 s^-1Specific activity α:5.419921022796 × 10⁺¹⁷ Bq g^-1
14648435.196746 Ci g^-1Spin and parity:
(nuclear angular momentum)(1-)Magnetic dipole moment:μ(μ_N) = 0.32(4)Quadrupole moment Q:+0.1(4) barn (100 fm²)Nuclear g-factor:g_l = 0.32Charge radius:5.5489(901) femtometer fmYear of discovery:1905

Radioactive Decay

Half-life T_½ = 60.55(6) min (minutes) respectively 3.633 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	Details	γ energy (intensity)
β^-	²¹²Po	64.06(6) %	2.2515(17) MeV	β^-: 0.8340(7) MeV [55.37(12) %] β^-: 0.5329(7) MeV [4.47(11) %]	0.727330(9) MeV [6.67(9) %]
α	²⁰⁸Tl	35.94(6) %	6.207262(28) MeV	α: 6.05078(3) MeV [25.13 %] 6.08988(3) MeV [9.75(5) %]
β^-, α	²⁰⁸Pb	0.014 %

Bi-212 is a radioactive intermediate of the thorium series emanating from Thorium-232 (see there for complete decay scheme).

Parent Nuclides

Direct parent isotopes are: ²¹⁶At, ²¹²Pb.

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
^212m1Bi	239(30) keV	25.0(2) min	(8-,9-)
^212m2Bi	1478(38) keV	7.0(3) min	(18-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 129) and isobaric (same nucleon number A = 212) with Bismuth-212. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 129	Isobar A = 212
78	²⁰⁷Pt
79	²⁰⁸Au
80	²⁰⁹Hg	²¹²Hg
81	²¹⁰Tl	²¹²Tl
82	²¹¹Pb	²¹²Pb
83	²¹²Bi	²¹²Bi
84	²¹³Po	²¹²Po
85	²¹⁴At	²¹²At
86	²¹⁵Rn	²¹²Rn
87	²¹⁶Fr	²¹²Fr
88	²¹⁷Ra	²¹²Ra
89	²¹⁸Ac	²¹²Ac
90	²¹⁹Th	²¹²Th
91	²²⁰Pa	²¹²Pa
92	²²¹U
93	²²²Np

External data and identifiers

CAS:14913-49-6InChI Key:JCXGWMGPZLAOME-AKLPVKDBSA-NSMILES:[212Bi]PubChem:ID 6335500Adopted Levels, Gammas:NuDat 212Bi

Literature and References

[1] - Ernest Rutherford, F. R. S.:
V. Bakerian Lecture. - The succession of changes radioactive bodies.
In: Philosophical Transactions A, 204, 372-386, (1905), DOI 10.1098/rsta.1905.0005.

[2] - Sara Franchi, Valerio Di Marco, Marianna Tosato:
Bismuth chelation for targeted alpha therapy: Current state of the art.
In: Nuclear Medicine and Biology, 114-115, (2022), DOI 10.1016/j.nucmedbio.2022.06.002.