Polonium-187

Properties and data of the isotope ¹⁸⁷Po.

Content

General data

Name of the isotope:Polonium-187; Po-187Symbol:¹⁸⁷Po or 18784PoMass number A:187 (= number of nucleons)Atomic number Z:84 (= number of protons)Neutrons N:103Isotopic mass:187.00304(3) u (atomic weight of Polonium-187)Nuclide mass:186.9569647 u (calculated nuclear mass without electrons)Mass excess:2.83174 MeVMass defect:1.546749036 u (per nucleus)Nuclear binding energy:1440.78744654 MeV (per nucleus)
7.7047457 MeV (average binding energy per nucleon)Separation energy:S_N = 9.34(4) MeV (first neutron)
S_P = 1.31(4) MeV (first proton)Half-life:1.40(25) msDecay constant λ:495.10512897139 s^-1Specific activity α:1.594434666921 × 10⁺²⁴ Bq g^-1
43092828835711 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2-.5/2-)Year of discovery:2005

Radioactive Decay

Half-life T_½ = 1.40(25) ms respectively 1.40 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁸³Pb	~100 %	7.979(15) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 103) and isobaric (same nucleon number A = 187) with Polonium-187. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 103	Isobar A = 187
60	¹⁶³Nd
62	¹⁶⁵Sm
63	¹⁶⁶Eu
64	¹⁶⁷Gd
65	¹⁶⁸Tb
66	¹⁶⁹Dy
67	¹⁷⁰Ho
68	¹⁷¹Er
69	¹⁷²Tm
70	¹⁷³Yb
71	¹⁷⁴Lu	¹⁸⁷Lu
72	¹⁷⁵Hf	¹⁸⁷Hf
73	¹⁷⁶Ta	¹⁸⁷Ta
74	¹⁷⁷W	¹⁸⁷W
75	¹⁷⁸Re	¹⁸⁷Re
76	¹⁷⁹Os	¹⁸⁷Os
77	¹⁸⁰Ir	¹⁸⁷Ir
78	¹⁸¹Pt	¹⁸⁷Pt
79	¹⁸²Au	¹⁸⁷Au
80	¹⁸³Hg	¹⁸⁷Hg
81	¹⁸⁴Tl	¹⁸⁷Tl
82	¹⁸⁵Pb	¹⁸⁷Pb
83	¹⁸⁶Bi	¹⁸⁷Bi
84	¹⁸⁷Po	¹⁸⁷Po