Polonium-208m

Properties and data of the isotope ^208mPo.

Contents

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

General data

Name of the isotope:Polonium-208m; Po-208mSymbol:^208mPo or 208m84PoMass number A:208 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:124Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.4761904761905 (= neutron-proton ratio)Neutron excess (N-Z):40Excitation energy:2528.22(4)Isotopic mass:207.9812456(19) u (atomic weight of Polonium-208m)Nuclide mass:207.9351703 u (calculated nuclear mass without electrons)Mass excess:-17.46961 MeVMass defect:1.750506672 u (per nucleus)Nuclear binding energy:1630.58646193 MeV (per nucleus)
7.83935799 MeV (average binding energy per nucleon)Half-life:350(20) nsDecay constant λ:1980420.5158856 s^-1Specific activity α:5.761532033126 × 10⁺²⁷ Bq g^-1
1.557170819763 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)8+Magnetic dipole moment:μ(μ_N) = +7.37(5)Quadrupole moment Q:0.90(4) barn (100 fm²)Nuclear g-factor:g_l = 0.92125

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
²⁰⁸Po		2.898(2) a	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 124) and isobaric (same nucleon number A = 208) with Polonium-208m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 124	Isobar A = 208
75	¹⁹⁹Re
76	²⁰⁰Os
77	²⁰¹Ir
78	²⁰²Pt	²⁰⁸Pt
79	²⁰³Au	²⁰⁸Au
80	²⁰⁴Hg	²⁰⁸Hg
81	²⁰⁵Tl	²⁰⁸Tl
82	²⁰⁶Pb	²⁰⁸Pb
83	²⁰⁷Bi	²⁰⁸Bi
84	²⁰⁸Po	²⁰⁸Po
85	²⁰⁹At	²⁰⁸At
86	²¹⁰Rn	²⁰⁸Rn
87	²¹¹Fr	²⁰⁸Fr
88	²¹²Ra	²⁰⁸Ra
89	²¹³Ac	²⁰⁸Ac
90	²¹⁴Th	²⁰⁸Th
91	²¹⁵Pa
92	²¹⁶U