Iridium-171

Properties and data of the isotope ¹⁷¹Ir.

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-171; Ir-171Symbol:¹⁷¹Ir or 17177IrMass number A:171 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:94Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.2207792207792 (= neutron-proton ratio)Neutron excess (N-Z):17Isotopic mass:170.97165(4) u (atomic weight of Iridium-171)Nuclide mass:170.9294138 u (calculated nuclear mass without electrons)Mass excess:-26.40785 MeVMass defect:1.445379568 u (per nucleus)Nuclear binding energy:1346.36239531 MeV (per nucleus)
7.8734643 MeV (average binding energy per nucleon)Separation energy:S_N = 11.12(10) MeV (first neutron)
S_P = -0.23(4) MeV (first proton)Half-life:3.2 sDecay constant λ:0.21660849392498 s^-1Specific activity α:7.673216834558 × 10⁺²⁰ Bq g^-1
20738423877.186 Ci g^-1Spin and parity:
(nuclear angular momentum)(1/2+)Year of discovery:1967

Radioactive Decay

Half-life T_½ = 3.2 s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁶⁷Re	15(2) %	5.994(13) MeV
EC/β⁺	¹⁷¹Os	85(2) %	7.89(4) MeV

Parent Nuclides

Direct parent isotope is: ¹⁷⁵Au.

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
^171mIr	+x keV	1.2(1) s	(11/2-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 94) and isobaric (same nucleon number A = 171) with Iridium-171. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 94	Isobar A = 171
54	¹⁴⁸Xe
55	¹⁴⁹Cs
56	¹⁵⁰Ba
57	¹⁵¹La
58	¹⁵²Ce
59	¹⁵³Pr
60	¹⁵⁴Nd
61	¹⁵⁵Pm
62	¹⁵⁶Sm
63	¹⁵⁷Eu
64	¹⁵⁸Gd
65	¹⁵⁹Tb	¹⁷¹Tb
66	¹⁶⁰Dy	¹⁷¹Dy
67	¹⁶¹Ho	¹⁷¹Ho
68	¹⁶²Er	¹⁷¹Er
69	¹⁶³Tm	¹⁷¹Tm
70	¹⁶⁴Yb	¹⁷¹Yb
71	¹⁶⁵Lu	¹⁷¹Lu
72	¹⁶⁶Hf	¹⁷¹Hf
73	¹⁶⁷Ta	¹⁷¹Ta
74	¹⁶⁸W	¹⁷¹W
75	¹⁶⁹Re	¹⁷¹Re
76	¹⁷⁰Os	¹⁷¹Os
77	¹⁷¹Ir	¹⁷¹Ir
78	¹⁷²Pt	¹⁷¹Pt
79	¹⁷³Au	¹⁷¹Au
80	¹⁷⁴Hg	¹⁷¹Hg