Polonium-212

Properties and data of the isotope ²¹²Po.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Polonium-212; Po-212Other names:Thorium C ´Symbol:²¹²Po or 21284PoMass number A:212 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:128Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.5238095238095 (= neutron-proton ratio)Neutron excess (N-Z):44Isotopic mass:211.9888679(12) u (atomic weight of Polonium-212)Nuclide mass:211.9427926 u (calculated nuclear mass without electrons)Mass excess:-10.36948 MeVMass defect:1.777544036 u (per nucleus)Nuclear binding energy:1655.77160427 MeV (per nucleus)
7.81024342 MeV (average binding energy per nucleon)Separation energy:S_N = 6.0082(5) MeV (first neutron)
S_P = 5.799(5) MeV (first proton)Half-life:0.299(2) μsDecay constant λ:2318217.9951838 s^-1Specific activity α:6.616414839353 × 10⁺²⁷ Bq g^-1
1.788220226852 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1906

Radioactive Decay

Half-life T_½ = 0.299(2) μs respectively 2.99 × 10^-7 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	²⁰⁸Pb	100 %	8.95420(11) MeV

Parent Nuclides

Direct parent isotopes are: ²¹⁶Rn, ²¹²Bi.

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
^212mPo	2922(15) keV	45.1(6) s	(18+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 128) and isobaric (same nucleon number A = 212) with Polonium-212. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 128	Isobar A = 212
77	²⁰⁵Ir
78	²⁰⁶Pt
79	²⁰⁷Au
80	²⁰⁸Hg	²¹²Hg
81	²⁰⁹Tl	²¹²Tl
82	²¹⁰Pb	²¹²Pb
83	²¹¹Bi	²¹²Bi
84	²¹²Po	²¹²Po
85	²¹³At	²¹²At
86	²¹⁴Rn	²¹²Rn
87	²¹⁵Fr	²¹²Fr
88	²¹⁶Ra	²¹²Ra
89	²¹⁷Ac	²¹²Ac
90	²¹⁸Th	²¹²Th
91	²¹⁹Pa	²¹²Pa
92	²²⁰U
93	²²¹Np
95	²²³Am