Osmium-191m

Properties and data of the isotope ^191mOs.

Contents

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

General data

Name of the isotope:Osmium-191m; Os-191mSymbol:^191mOs or 191m76OsMass number A:191 (= number of nucleons)Atomic number Z:76 (= number of protons)Neutrons N:115Isotopic mass:190.9609282(7) u (atomic weight of Osmium-191m)
Excitation energy: 74.382(3) keVNuclide mass:190.9192404 u (calculated nuclear mass without electrons)Mass excess:-36.39515 MeVMass defect:1.630239572 u (per nucleus)Nuclear binding energy:1518.55837988 MeV (per nucleus)
7.95056743 MeV (average binding energy per nucleon)Half-life:13.10(5) hDecay constant λ:1.469777736556 × 10^-5 s^-1Specific activity α:4.658530822284 × 10⁺¹⁶ Bq g^-1
1259062.3844013 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-

Radioactive Decay

Half-life T_½ = 13.10(5) h (hours) respectively 4.7160 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁹¹Os	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
¹⁹¹Os		15.4(1) d	9/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 115) and isobaric (same nucleon number A = 191) with Osmium-191m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 115	Isobar A = 191
70	¹⁸⁵Yb
71	¹⁸⁶Lu
72	¹⁸⁷Hf
73	¹⁸⁸Ta	¹⁹¹Ta
74	¹⁸⁹W	¹⁹¹W
75	¹⁹⁰Re	¹⁹¹Re
76	¹⁹¹Os	¹⁹¹Os
77	¹⁹²Ir	¹⁹¹Ir
78	¹⁹³Pt	¹⁹¹Pt
79	¹⁹⁴Au	¹⁹¹Au
80	¹⁹⁵Hg	¹⁹¹Hg
81	¹⁹⁶Tl	¹⁹¹Tl
82	¹⁹⁷Pb	¹⁹¹Pb
83	¹⁹⁸Bi	¹⁹¹Bi
84	¹⁹⁹Po	¹⁹¹Po
85	²⁰⁰At	¹⁹¹At
86	²⁰¹Rn
87	²⁰²Fr
88	²⁰³Ra
89	²⁰⁴Ac