Polonium-197

Properties and data of the isotope ¹⁹⁷Po.

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-197; Po-197Symbol:¹⁹⁷Po or 19784PoMass number A:197 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:113Isotopic mass:196.98566(5) u (atomic weight of Polonium-197)Nuclide mass:196.9395847 u (calculated nuclear mass without electrons)Mass excess:-13.35762 MeVMass defect:1.650778196 u (per nucleus)Nuclear binding energy:1537.6899849 MeV (per nucleus)
7.80553292 MeV (average binding energy per nucleon)Separation energy:S_N = 7.96(5) MeV (first neutron)
S_P = 2.64(6) MeV (first proton)Half-life:84(16) sDecay constant λ:0.0082517521495232 s^-1Specific activity α:2.535368050291 × 10⁺¹⁹ Bq g^-1
685234608.18689 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2-)Magnetic dipole moment:μ(μ_N) = -0.882(65)Quadrupole moment Q:-0.44(20) barn (100 fm²)Nuclear g-factor:g_l = -0.588Year of discovery:1965

Radioactive Decay

Half-life T_½ = 84(16) s respectively 8.4 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹³Pb	44(7) %	6.412(3) MeV
EC/β⁺	¹⁹⁷Bi	56(7) %	6.33(5) MeV

Parent Nuclides

Direct parent isotopes are: ²⁰¹Rn, ¹⁹⁷At.

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
^197mPo	204 keV	32(2) s	(13/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 113) and isobaric (same nucleon number A = 197) with Polonium-197. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 113	Isobar A = 197
70	¹⁸³Yb
71	¹⁸⁴Lu
72	¹⁸⁵Hf
73	¹⁸⁶Ta
74	¹⁸⁷W	¹⁹⁷W
75	¹⁸⁸Re	¹⁹⁷Re
76	¹⁸⁹Os	¹⁹⁷Os
77	¹⁹⁰Ir	¹⁹⁷Ir
78	¹⁹¹Pt	¹⁹⁷Pt
79	¹⁹²Au	¹⁹⁷Au
80	¹⁹³Hg	¹⁹⁷Hg
81	¹⁹⁴Tl	¹⁹⁷Tl
82	¹⁹⁵Pb	¹⁹⁷Pb
83	¹⁹⁶Bi	¹⁹⁷Bi
84	¹⁹⁷Po	¹⁹⁷Po
85	¹⁹⁸At	¹⁹⁷At
86	¹⁹⁹Rn	¹⁹⁷Rn
87	²⁰⁰Fr
88	²⁰¹Ra