Iridium-168

Properties and data of the isotope ¹⁶⁸Ir.

Contents

General data

Name of the isotope:Iridium-168; Ir-168Symbol:¹⁶⁸Ir or 16877IrMass number A:168 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:91Isotopic mass:167.97996(6) u (atomic weight of Iridium-168)Nuclide mass:167.9377238 u (calculated nuclear mass without electrons)Mass excess:-18.66714 MeVMass defect:1.41107482 u (per nucleus)Nuclear binding energy:1314.40772838 MeV (per nucleus)
7.82385553 MeV (average binding energy per nucleon)Separation energy:S_N = 9.67(6) MeV (first neutron)
S_P = -0.55(9) MeV (first proton)Half-life:222 msDecay constant λ:3.1222845971169 s^-1Specific activity α:1.125918422074 × 10⁺²² Bq g^-1
304302276236.43 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:1978

Radioactive Decay

Half-life T_½ = 222 ms respectively 2.22 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy
α	¹⁶⁴Re	≤ 100 %	6.381(9) MeV
p	¹⁶⁷Os	?
EC/β⁺	¹⁶⁸Os	?	11,33(6) MeV

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
¹⁶⁸Ir	+x keV	159 ms

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 91) and isobaric (same nucleon number A = 168) with Iridium-168. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 91	Isobar A = 168
52	¹⁴³Te
53	¹⁴⁴I
54	¹⁴⁵Xe
55	¹⁴⁶Cs
56	¹⁴⁷Ba
57	¹⁴⁸La
58	¹⁴⁹Ce
59	¹⁵⁰Pr
60	¹⁵¹Nd
61	¹⁵²Pm
62	¹⁵³Sm
63	¹⁵⁴Eu	¹⁶⁸Eu
64	¹⁵⁵Gd	¹⁶⁸Gd
65	¹⁵⁶Tb	¹⁶⁸Tb
66	¹⁵⁷Dy	¹⁶⁸Dy
67	¹⁵⁸Ho	¹⁶⁸Ho
68	¹⁵⁹Er	¹⁶⁸Er
69	¹⁶⁰Tm	¹⁶⁸Tm
70	¹⁶¹Yb	¹⁶⁸Yb
71	¹⁶²Lu	¹⁶⁸Lu
72	¹⁶³Hf	¹⁶⁸Hf
73	¹⁶⁴Ta	¹⁶⁸Ta
74	¹⁶⁵W	¹⁶⁸W
75	¹⁶⁶Re	¹⁶⁸Re
76	¹⁶⁷Os	¹⁶⁸Os
77	¹⁶⁸Ir	¹⁶⁸Ir
78	¹⁶⁹Pt	¹⁶⁸Pt
79	¹⁷⁰Au
80	¹⁷¹Hg