Polonium-210m

Properties and data of the isotope ^210mPo.

Contents

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

General data

Name of the isotope:Polonium-210m; Po-210mSymbol:^210mPo or 210m84PoMass number A:210 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:126Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.5 (= neutron-proton ratio)Neutron excess (N-Z):42Excitation energy:5057.65(5) keVIsotopic mass:209.9828736(12) u (atomic weight of Polonium-210m)Nuclide mass:209.9367983 u (calculated nuclear mass without electrons)Mass excess:-15.95314 MeVMass defect:1.766208504 u (per nucleus)Nuclear binding energy:1645.21262422 MeV (per nucleus)
7.83434583 MeV (average binding energy per nucleon)Half-life:263(5) nsDecay constant λ:2635540.6104941 s^-1Specific activity α:7.594065453817 × 10⁺²⁷ Bq g^-1
2.052450122653 × 10⁺¹⁷ Ci g^-1Spin and parity:
(nuclear angular momentum)16+Magnetic dipole moment:μ(μ_N) = 9.84(8)Quadrupole moment Q:-1.297(20) barn (100 fm²)Nuclear g-factor:g_l = 0.615

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
²¹⁰Po		138.376(2) d	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 126) and isobaric (same nucleon number A = 210) with Polonium-210m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 126	Isobar A = 210
76	²⁰²Os
77	²⁰³Ir
78	²⁰⁴Pt
79	²⁰⁵Au	²¹⁰Au
80	²⁰⁶Hg	²¹⁰Hg
81	²⁰⁷Tl	²¹⁰Tl
82	²⁰⁸Pb	²¹⁰Pb
83	²⁰⁹Bi	²¹⁰Bi
84	²¹⁰Po	²¹⁰Po
85	²¹¹At	²¹⁰At
86	²¹²Rn	²¹⁰Rn
87	²¹³Fr	²¹⁰Fr
88	²¹⁴Ra	²¹⁰Ra
89	²¹⁵Ac	²¹⁰Ac
90	²¹⁶Th	²¹⁰Th
91	²¹⁷Pa	²¹⁰Pa
92	²¹⁸U
93	²¹⁹Np