Iridium-189m2

Properties and data of the isotope ^189m2Ir.

Contents

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

General data

Name of the isotope:Iridium-189m2; Ir-189m2Symbol:^189m2Ir or 189m277IrMass number A:189 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:112Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4545454545455 (= neutron-proton ratio)Neutron excess (N-Z):35Excitation energy:2333.2(5) keVIsotopic mass:188.958723(13) u (atomic weight of Iridium-189m2)Nuclide mass:188.9164868 u (calculated nuclear mass without electrons)Mass excess:-38.44928 MeVMass defect:1.614275056 u (per nucleus)Nuclear binding energy:1503.68752901 MeV (per nucleus)
7.95601867 MeV (average binding energy per nucleon)Half-life:3.7(2) msDecay constant λ:187.33707582701 s^-1Specific activity α:6.000905632547 × 10⁺²³ Bq g^-1
16218663871750 Ci g^-1Spin and parity:
(nuclear angular momentum)(25/2)+

Radioactive Decay

Half-life T_½ = 3.7(2) ms respectively 3.7 × 10^-3 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁸⁹Ir	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
^189m1Ir	372.17(4) keV	13.3(3) ms	11/2-
¹⁸⁹Ir		13.2(1) d	3/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 112) and isobaric (same nucleon number A = 189) with Iridium-189m2. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 112	Isobar A = 189
70	¹⁸²Yb
71	¹⁸³Lu
72	¹⁸⁴Hf	¹⁸⁹Hf
73	¹⁸⁵Ta	¹⁸⁹Ta
74	¹⁸⁶W	¹⁸⁹W
75	¹⁸⁷Re	¹⁸⁹Re
76	¹⁸⁸Os	¹⁸⁹Os
77	¹⁸⁹Ir	¹⁸⁹Ir
78	¹⁹⁰Pt	¹⁸⁹Pt
79	¹⁹¹Au	¹⁸⁹Au
80	¹⁹²Hg	¹⁸⁹Hg
81	¹⁹³Tl	¹⁸⁹Tl
82	¹⁹⁴Pb	¹⁸⁹Pb
83	¹⁹⁵Bi	¹⁸⁹Bi
84	¹⁹⁶Po	¹⁸⁹Po
85	¹⁹⁷At	¹⁸⁹At
86	¹⁹⁸Rn
87	¹⁹⁹Fr