Iridium-195

Properties and data of the isotope ¹⁹⁵Ir.

Content

General data

Name of the isotope:Iridium-195; Ir-195Symbol:¹⁹⁵Ir or 19577IrMass number A:195 (= number of nucleons)Atomic number Z:77 (= number of protons)Neutrons N:118Isotopic mass:194.9659770(14) u (atomic weight of Iridium-195)Nuclide mass:194.9237408 u (calculated nuclear mass without electrons)Mass excess:-31.69222 MeVMass defect:1.659010552 u (per nucleus)Nuclear binding energy:1545.35837512 MeV (per nucleus)
7.92491474 MeV (average binding energy per nucleon)Separation energy:S_N = 7.23186(6) MeV (first neutron)
S_P = 6.5461(20) MeV (first proton)Half-life:2.29(17) hDecay constant λ:8.407898842308 × 10^-5 s^-1Specific activity α:2.609976864148 × 10⁺¹⁷ Bq g^-1
7053991.5247259 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2+Year of discovery:1952

Radioactive Decay

Half-life T_½ = 2.29(17) h (hours) respectively 8.244 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁹⁵Pt	100 %	1.1016(13) 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
^195mIr	100(5) keV	3.67(82) h	11/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 118) and isobaric (same nucleon number A = 195) with Iridium-195. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 118	Isobar A = 195
72	¹⁹⁰Hf
73	¹⁹¹Ta
74	¹⁹²W	¹⁹⁵W
75	¹⁹³Re	¹⁹⁵Re
76	¹⁹⁴Os	¹⁹⁵Os
77	¹⁹⁵Ir	¹⁹⁵Ir
78	¹⁹⁶Pt	¹⁹⁵Pt
79	¹⁹⁷Au	¹⁹⁵Au
80	¹⁹⁸Hg	¹⁹⁵Hg
81	¹⁹⁹Tl	¹⁹⁵Tl
82	²⁰⁰Pb	¹⁹⁵Pb
83	²⁰¹Bi	¹⁹⁵Bi
84	²⁰²Po	¹⁹⁵Po
85	²⁰³At	¹⁹⁵At
86	²⁰⁴Rn	¹⁹⁵Rn
87	²⁰⁵Fr
88	²⁰⁶Ra
89	²⁰⁷Ac
90	²⁰⁸Th