Polonium-205m2

Properties and data of the isotope ^205m2Po.

Contents

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

General data

Name of the isotope:Polonium-205m2; Po-205m2Symbol:^205m2Po or 205m284PoMass number A:205 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:121Isotopic mass:204.981190(11) u (atomic weight of Polonium-205m2)
Excitation energy: 880.31(7) keVNuclide mass:204.9351147 u (calculated nuclear mass without electrons)Mass excess:-17.5214 MeVMass defect:1.724567524 u (per nucleus)Nuclear binding energy:1606.4243012 MeV (per nucleus)
7.8362161 MeV (average binding energy per nucleon)Half-life:0.645(20) msDecay constant λ:1074.6467915658 s^-1Specific activity α:3.172389388964 × 10⁺²⁴ Bq g^-1
85740253755808 Ci g^-1Spin and parity:
(nuclear angular momentum)13/2+Magnetic dipole moment:μ(μ_N) = - 0.95(5)Nuclear g-factor:g_l = -0.14615384615385

Radioactive Decay

Half-life T_½ = 0.645(20) ms respectively 6.45 × 10^-4 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	²⁰⁵Po	100 %

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
²⁰⁵Po		1.74(8) h	5/2-
^205m1Po	143.166(17) keV	310(60) ns	1/2-
^205m3Po	1461.21(21) keV	57.4(9) ms	19/2-
^205m4Po	3087.2(4) keV	115(10) ns	29/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 121) and isobaric (same nucleon number A = 205) with Polonium-205m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 121	Isobar A = 205
73	¹⁹⁴Ta
74	¹⁹⁵W
75	¹⁹⁶Re
76	¹⁹⁷Os
77	¹⁹⁸Ir	²⁰⁵Ir
78	¹⁹⁹Pt	²⁰⁵Pt
79	²⁰⁰Au	²⁰⁵Au
80	²⁰¹Hg	²⁰⁵Hg
81	²⁰²Tl	²⁰⁵Tl
82	²⁰³Pb	²⁰⁵Pb
83	²⁰⁴Bi	²⁰⁵Bi
84	²⁰⁵Po	²⁰⁵Po
85	²⁰⁶At	²⁰⁵At
86	²⁰⁷Rn	²⁰⁵Rn
87	²⁰⁸Fr	²⁰⁵Fr
88	²⁰⁹Ra	²⁰⁵Ra
89	²¹⁰Ac	²⁰⁵Ac
90	²¹¹Th
91	²¹²Pa