Polonium-203

Properties and data of the isotope ²⁰³Po.

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-203; Po-203Symbol:²⁰³Po or 20384PoMass number A:203 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:119Isotopic mass:202.981416(9) u (atomic weight of Polonium-203)Nuclide mass:202.9353407 u (calculated nuclear mass without electrons)Mass excess:-17.31088 MeVMass defect:1.707011692 u (per nucleus)Nuclear binding energy:1590.07114903 MeV (per nucleus)
7.8328628 MeV (average binding energy per nucleon)Separation energy:S_N = 7.441(12) MeV (first neutron)
S_P = 3.858(18) MeV (first proton)Half-life:36.7(5) minDecay constant λ:0.00031478073594911 s^-1Specific activity α:9.384425405347 × 10⁺¹⁷ Bq g^-1
25363311.906344 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Magnetic dipole moment:μ(μ_N) = +0.7405(15)Quadrupole moment Q:+0.17(10) barn (100 fm²)Nuclear g-factor:g_l = 0.2962Year of discovery:1951

Radioactive Decay

Half-life T_½ = 36.7(5) min (minutes) respectively 2.202 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹⁹Pb	0.11(2) %	5.496(5) MeV
EC/β⁺	²⁰³Bi	99.89(2) %	4.214(15) MeV

Parent Nuclides

Direct parent isotopes are: ²⁰⁷Rn, ²⁰³At.

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
^203m1Po	641.68(17) keV	45(2) s	13/2+
^203m2Po	2158.5(6) keV	200 ns

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 119) and isobaric (same nucleon number A = 203) with Polonium-203. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 119	Isobar A = 203
73	¹⁹²Ta
74	¹⁹³W
75	¹⁹⁴Re
76	¹⁹⁵Os	²⁰³Os
77	¹⁹⁶Ir	²⁰³Ir
78	¹⁹⁷Pt	²⁰³Pt
79	¹⁹⁸Au	²⁰³Au
80	¹⁹⁹Hg	²⁰³Hg
81	²⁰⁰Tl	²⁰³Tl
82	²⁰¹Pb	²⁰³Pb
83	²⁰²Bi	²⁰³Bi
84	²⁰³Po	²⁰³Po
85	²⁰⁴At	²⁰³At
86	²⁰⁵Rn	²⁰³Rn
87	²⁰⁶Fr	²⁰³Fr
88	²⁰⁷Ra	²⁰³Ra
89	²⁰⁸Ac	²⁰³Ac
90	²⁰⁹Th
91	²¹⁰Pa