Iridium-177

Properties and data of the isotope ¹⁷⁷Ir.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Iridium-177; Ir-177Symbol:¹⁷⁷Ir or 17777IrMass number A:177 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:100Isotopic mass:176.961301(21) u (atomic weight of Iridium-177)Nuclide mass:176.9190648 u (calculated nuclear mass without electrons)Mass excess:-36.04789 MeVMass defect:1.507718064 u (per nucleus)Nuclear binding energy:1404.43033031 MeV (per nucleus)
7.93463463 MeV (average binding energy per nucleon)Separation energy:S_N = 10.240(26) MeV (first neutron)
S_P = 1.24(3) MeV (first proton)Half-life:29.8(17) sDecay constant λ:0.023259972502012 s^-1Specific activity α:7.958797204850 × 10⁺¹⁹ Bq g^-1
2151026271.5812 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Year of discovery:1967

Radioactive Decay

Half-life T_½ = 29.8(17) s respectively 2.98 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁷³Re	0.06(1) %	5.08(3) MeV
EC/β⁺	¹⁷⁷Os	99.94(1) %	5.909(25) MeV

Parent Nuclides

Direct parent isotopes are: ¹⁸¹Au, ¹⁷⁷Pt.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 100) and isobaric (same nucleon number A = 177) with Iridium-177. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 100	Isobar A = 177
58	¹⁵⁸Ce
59	¹⁵⁹Pr
60	¹⁶⁰Nd
61	¹⁶¹Pm
62	¹⁶²Sm
63	¹⁶³Eu
64	¹⁶⁴Gd
65	¹⁶⁵Tb
66	¹⁶⁶Dy
67	¹⁶⁷Ho
68	¹⁶⁸Er	¹⁷⁷Er
69	¹⁶⁹Tm	¹⁷⁷Tm
70	¹⁷⁰Yb	¹⁷⁷Yb
71	¹⁷¹Lu	¹⁷⁷Lu
72	¹⁷²Hf	¹⁷⁷Hf
73	¹⁷³Ta	¹⁷⁷Ta
74	¹⁷⁴W	¹⁷⁷W
75	¹⁷⁵Re	¹⁷⁷Re
76	¹⁷⁶Os	¹⁷⁷Os
77	¹⁷⁷Ir	¹⁷⁷Ir
78	¹⁷⁸Pt	¹⁷⁷Pt
79	¹⁷⁹Au	¹⁷⁷Au
80	¹⁸⁰Hg	¹⁷⁷Hg
81	¹⁸¹Tl	¹⁷⁷Tl
82	¹⁸²Pb