Iridium-197m

Properties and data of the isotope ^197mIr.

Contents

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

General data

Name of the isotope:Iridium-197m; Ir-197mSymbol:^197mIr or 197m77IrMass number A:197 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:120Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.5584415584416 (= neutron-proton ratio)Neutron excess (N-Z):43Excitation energy:115(5) keVIsotopic mass:196.969657(22) u (atomic weight of Iridium-197m)Nuclide mass:196.9274208 u (calculated nuclear mass without electrons)Mass excess:-28.26432 MeVMass defect:1.672660384 u (per nucleus)Nuclear binding energy:1558.07311173 MeV (per nucleus)
7.90900057 MeV (average binding energy per nucleon)Half-life:8.9(3) minDecay constant λ:0.0012980284280149 s^-1Specific activity α:3.98821940495 × 10⁺¹⁸ Bq g^-1
107789713.64738 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2-

Radioactive Decay

Half-life T_½ = 8.9(3) min (minutes) respectively 5.34 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁹⁷Pt	99.75(10) %
Iso	¹⁹⁷Ir	0.25(10) %

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
¹⁹⁷Ir		5.8(5) min	3/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 120) and isobaric (same nucleon number A = 197) with Iridium-197m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 120	Isobar A = 197
73	¹⁹³Ta
74	¹⁹⁴W	¹⁹⁷W
75	¹⁹⁵Re	¹⁹⁷Re
76	¹⁹⁶Os	¹⁹⁷Os
77	¹⁹⁷Ir	¹⁹⁷Ir
78	¹⁹⁸Pt	¹⁹⁷Pt
79	¹⁹⁹Au	¹⁹⁷Au
80	²⁰⁰Hg	¹⁹⁷Hg
81	²⁰¹Tl	¹⁹⁷Tl
82	²⁰²Pb	¹⁹⁷Pb
83	²⁰³Bi	¹⁹⁷Bi
84	²⁰⁴Po	¹⁹⁷Po
85	²⁰⁵At	¹⁹⁷At
86	²⁰⁶Rn	¹⁹⁷Rn
87	²⁰⁷Fr
88	²⁰⁸Ra
89	²⁰⁹Ac
90	²¹⁰Th