Iridium-186m

Properties and data of the isotope ^186mIr.

Contents

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

General data

Name of the isotope:Iridium-186m; Ir-186mSymbol:^186mIr or 186m77IrMass number A:186 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:109Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.4155844155844 (= neutron-proton ratio)Neutron excess (N-Z):32Excitation energy:+x keVIsotopic mass:185.957947(18) u (atomic weight of Iridium-186m)Nuclide mass:185.9157108 u (calculated nuclear mass without electrons)Mass excess:-39.17212 MeVMass defect:1.589056308 u (per nucleus)Nuclear binding energy:1480.19641656 MeV (per nucleus)
7.95804525 MeV (average binding energy per nucleon)Half-life:1.90(5) hDecay constant λ:0.00010133730709941 s^-1Specific activity α:3.298743447131 × 10⁺¹⁷ Bq g^-1
8915522.8300846 Ci g^-1Spin and parity:
(nuclear angular momentum)2-Magnetic dipole moment:μ(μ_N) = 0.638(8)Quadrupole moment Q:+ 1.456(17) barn (100 fm²)Nuclear g-factor:g_l = 0.319

Radioactive Decay

Half-life T_½ = 1.90(5) h (hours) respectively 6.840 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	¹⁸⁶Os	ca. 75 %
Iso	¹⁸⁶Ir	ca. 25 %

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
¹⁸⁶Ir		16.64(3) h	5+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 109) and isobaric (same nucleon number A = 186) with Iridium-186m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 109	Isobar A = 186
68	¹⁷⁷Er
69	¹⁷⁸Tm
70	¹⁷⁹Yb
71	¹⁸⁰Lu	¹⁸⁶Lu
72	¹⁸¹Hf	¹⁸⁶Hf
73	¹⁸²Ta	¹⁸⁶Ta
74	¹⁸³W	¹⁸⁶W
75	¹⁸⁴Re	¹⁸⁶Re
76	¹⁸⁵Os	¹⁸⁶Os
77	¹⁸⁶Ir	¹⁸⁶Ir
78	¹⁸⁷Pt	¹⁸⁶Pt
79	¹⁸⁸Au	¹⁸⁶Au
80	¹⁸⁹Hg	¹⁸⁶Hg
81	¹⁹⁰Tl	¹⁸⁶Tl
82	¹⁹¹Pb	¹⁸⁶Pb
83	¹⁹²Bi	¹⁸⁶Bi
84	¹⁹³Po	¹⁸⁶Po
85	¹⁹⁴At
86	¹⁹⁵Rn