Bismuth-191m1

Properties and data of the isotope ^191m1Bi.

Contents

General data

Name of the isotope:Bismuth-191m1; Bi-191m1Symbol:^191m1Bi or 191m183BiMass number A:191 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:108Isotopic mass:190.985787(8) u (atomic weight of Bismuth-191m1)
Excitation energy: 240(4) keVNuclide mass:190.9402601 u (calculated nuclear mass without electrons)Mass excess:-13.23932 MeVMass defect:1.599501584 u (per nucleus)Nuclear binding energy:1489.92612849 MeV (per nucleus)
7.80066036 MeV (average binding energy per nucleon)Half-life:125(13) msDecay constant λ:5.5451774444796 s^-1Specific activity α:1.757570508631 × 10⁺²² Bq g^-1
475019056386.92 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2+)

Radioactive Decay

Half-life T_½ = 125(13) ms respectively 1.25 × 10^-1 seconds s.

Decay mode	Daughter	Probability
α	¹⁸⁷Tl	68(5) %
EC/β⁺	¹⁹¹Pb	?
Iso	¹⁹¹Bi	32(5) %

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
¹⁹¹Bi		12.4(3) s	(9/2-)
^191m2Bi	429.7(4) keV	562(10) ns	(13/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 108) and isobaric (same nucleon number A = 191) with Bismuth-191m1. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 108	Isobar A = 191
66	¹⁷⁴Dy
67	¹⁷⁵Ho
68	¹⁷⁶Er
69	¹⁷⁷Tm
70	¹⁷⁸Yb
71	¹⁷⁹Lu
72	¹⁸⁰Hf
73	¹⁸¹Ta	¹⁹¹Ta
74	¹⁸²W	¹⁹¹W
75	¹⁸³Re	¹⁹¹Re
76	¹⁸⁴Os	¹⁹¹Os
77	¹⁸⁵Ir	¹⁹¹Ir
78	¹⁸⁶Pt	¹⁹¹Pt
79	¹⁸⁷Au	¹⁹¹Au
80	¹⁸⁸Hg	¹⁹¹Hg
81	¹⁸⁹Tl	¹⁹¹Tl
82	¹⁹⁰Pb	¹⁹¹Pb
83	¹⁹¹Bi	¹⁹¹Bi
84	¹⁹²Po	¹⁹¹Po
85	¹⁹³At	¹⁹¹At
86	¹⁹⁴Rn