Lead-195

Properties and data of the isotope ¹⁹⁵Pb.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Lead-195; Pb-195Symbol:¹⁹⁵Pb or 19582PbMass number A:195 (= number of nucleons)Atomic number Z:82 (= number of protons)Neutrons N:113Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.3780487804878 (= neutron-proton ratio)Neutron excess (N-Z):31Isotopic mass:194.974549(19) u (atomic weight of Lead-195)Nuclide mass:194.9295706 u (calculated nuclear mass without electrons)Mass excess:-23.70745 MeVMass defect:1.646239132 u (per nucleus)Nuclear binding energy:1533.46187402 MeV (per nucleus)
7.86390705 MeV (average binding energy per nucleon)Separation energy:S_N = 7.571(25) MeV (first neutron)
S_P = 4.059(23) MeV (first proton)Half-life:15 minDecay constant λ:0.00077016353395549 s^-1Specific activity α:2.390738807560 × 10⁺¹⁸ Bq g^-1
64614562.366489 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Charge radius:5.4389(45) femtometer fmYear of discovery:1957

Radioactive Decay

Half-life T_½ = 15 min (minutes) respectively 9.00 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β⁺	¹⁹⁵Tl	100 %	4.448(21) MeV

Parent Nuclides

Direct parent isotopes are: ¹⁹⁵Bi, ¹⁹⁹Po.

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
^195m1Pb	202.9(7) keV	15.0(12) min	13/2+
^195m2Pb	1759.0(7) keV	10.0(7) μs	21/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 113) and isobaric (same nucleon number A = 195) with Lead-195. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 113	Isobar A = 195
70	¹⁸³Yb
71	¹⁸⁴Lu
72	¹⁸⁵Hf
73	¹⁸⁶Ta
74	¹⁸⁷W	¹⁹⁵W
75	¹⁸⁸Re	¹⁹⁵Re
76	¹⁸⁹Os	¹⁹⁵Os
77	¹⁹⁰Ir	¹⁹⁵Ir
78	¹⁹¹Pt	¹⁹⁵Pt
79	¹⁹²Au	¹⁹⁵Au
80	¹⁹³Hg	¹⁹⁵Hg
81	¹⁹⁴Tl	¹⁹⁵Tl
82	¹⁹⁵Pb	¹⁹⁵Pb
83	¹⁹⁶Bi	¹⁹⁵Bi
84	¹⁹⁷Po	¹⁹⁵Po
85	¹⁹⁸At	¹⁹⁵At
86	¹⁹⁹Rn	¹⁹⁵Rn
87	²⁰⁰Fr
88	²⁰¹Ra