Iridium-202

Properties and data of the isotope ²⁰²Ir.

Contents

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

General data

Name of the isotope:Iridium-202; Ir-202Symbol:²⁰²Ir or 20277IrMass number A:202 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:125Nucleon pairing (Z - N):odd - oddNuclear ratio (N/Z ratio):1.6233766233766 (= neutron-proton ratio)Neutron excess (N-Z):48Isotopic mass:201.98199(32) u (atomic weight of Iridium-202)Nuclide mass:201.9397538 u (calculated nuclear mass without electrons)Mass excess:-16.77621 MeVMass defect:1.703651964 u (per nucleus)Nuclear binding energy:1586.94158255 MeV (per nucleus)
7.85614645 MeV (average binding energy per nucleon)Separation energy:S_N = 4.95(36) MeV (first neutron)
S_P = 8.83(42) MeV (first proton)Half-life:11(3) sDecay constant λ:0.063013380050904 s^-1Specific activity α:1.887937565807 × 10⁺²⁰ Bq g^-1
5102533961.6414 Ci g^-1Spin and parity:
(nuclear angular momentum)(1-.2-)Year of discovery:2008

Radioactive Decay

Half-life T_½ = 11(3) s respectively 1.1 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁰²Pt	100 %	5.92(30) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 202) with Iridium-202. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 125	Isobar A = 202
76	²⁰¹Os	²⁰²Os
77	²⁰²Ir	²⁰²Ir
78	²⁰³Pt	²⁰²Pt
79	²⁰⁴Au	²⁰²Au
80	²⁰⁵Hg	²⁰²Hg
81	²⁰⁶Tl	²⁰²Tl
82	²⁰⁷Pb	²⁰²Pb
83	²⁰⁸Bi	²⁰²Bi
84	²⁰⁹Po	²⁰²Po
85	²¹⁰At	²⁰²At
86	²¹¹Rn	²⁰²Rn
87	²¹²Fr	²⁰²Fr
88	²¹³Ra	²⁰²Ra
89	²¹⁴Ac
90	²¹⁵Th
91	²¹⁶Pa
92	²¹⁷U