Polonium-204m

Properties and data of the isotope ²⁰⁴Po.

Content

General data

Name of the isotope:Polonium-204m; Po-204mSymbol:²⁰⁴Po or 20484PoMass number A:204 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:120Isotopic mass:203.980310(12) u (atomic weight of Polonium-204m)
Excitation energy: 1639.03(6) keVNuclide mass:203.9342347 u (calculated nuclear mass without electrons)Mass excess:-18.34112 MeVMass defect:1.716782608 u (per nucleus)Nuclear binding energy:1599.17269866 MeV (per nucleus)
7.83908186 MeV (average binding energy per nucleon)Half-life:Decay constant λ:4500955.7179217 s^-1Specific activity α:1.33524085407 × 10⁺²⁸ Bq g^-1
3.608759065059 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)8+Magnetic dipole moment:μ(μ_N) = +7.38(10)Quadrupole moment Q:1.14(5) barn (100 fm²)Nuclear g-factor:g_l = 0.9225

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
²⁰⁴Po		3.519(12) h	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 120) and isobaric (same nucleon number A = 204) with Polonium-204m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 120	Isobar A = 204
73	¹⁹³Ta
74	¹⁹⁴W
75	¹⁹⁵Re
76	¹⁹⁶Os
77	¹⁹⁷Ir	²⁰⁴Ir
78	¹⁹⁸Pt	²⁰⁴Pt
79	¹⁹⁹Au	²⁰⁴Au
80	²⁰⁰Hg	²⁰⁴Hg
81	²⁰¹Tl	²⁰⁴Tl
82	²⁰²Pb	²⁰⁴Pb
83	²⁰³Bi	²⁰⁴Bi
84	²⁰⁴Po	²⁰⁴Po
85	²⁰⁵At	²⁰⁴At
86	²⁰⁶Rn	²⁰⁴Rn
87	²⁰⁷Fr	²⁰⁴Fr
88	²⁰⁸Ra	²⁰⁴Ra
89	²⁰⁹Ac	²⁰⁴Ac
90	²¹⁰Th