Bismuth-195

Properties and data of the isotope ¹⁹⁵Bi.

Contents

General data

Name of the isotope:Bismuth-195; Bi-195Symbol:¹⁹⁵Bi or 19583BiMass number A:195 (= number of nucleons)Atomic number Z:83 (= number of protons)Neutrons N:112Isotopic mass:194.980649(6) u (atomic weight of Bismuth-195)Nuclide mass:194.9351221 u (calculated nuclear mass without electrons)Mass excess:-18.02534 MeVMass defect:1.639299248 u (per nucleus)Nuclear binding energy:1526.99741372 MeV (per nucleus)
7.83075597 MeV (average binding energy per nucleon)Separation energy:S_N = 10.068(8) MeV (first neutron)
S_P = 1.107(18) MeV (first proton)Half-life:183(4) sDecay constant λ:0.0037876895112565 s^-1Specific activity α:1.17577318404 × 10⁺¹⁹ Bq g^-1
317776536.22865 Ci g^-1Spin and parity:
(nuclear angular momentum)(9/2-)Year of discovery:1971

Radioactive Decay

Half-life T_½ = 183(4) s respectively 1.83 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁹¹Tl	0.03(2) %	5.832(5) MeV
EC/β⁺	¹⁹⁵Pb	99.97(2) %	5.682(19) MeV

Parent Nuclides

Direct parent isotope is: ¹⁹⁹At.

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
^195mBi	401(7) keV	87(1) s	(1/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 112) and isobaric (same nucleon number A = 195) with Bismuth-195. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 112	Isobar A = 195
70	¹⁸²Yb
71	¹⁸³Lu
72	¹⁸⁴Hf
73	¹⁸⁵Ta
74	¹⁸⁶W	¹⁹⁵W
75	¹⁸⁷Re	¹⁹⁵Re
76	¹⁸⁸Os	¹⁹⁵Os
77	¹⁸⁹Ir	¹⁹⁵Ir
78	¹⁹⁰Pt	¹⁹⁵Pt
79	¹⁹¹Au	¹⁹⁵Au
80	¹⁹²Hg	¹⁹⁵Hg
81	¹⁹³Tl	¹⁹⁵Tl
82	¹⁹⁴Pb	¹⁹⁵Pb
83	¹⁹⁵Bi	¹⁹⁵Bi
84	¹⁹⁶Po	¹⁹⁵Po
85	¹⁹⁷At	¹⁹⁵At
86	¹⁹⁸Rn	¹⁹⁵Rn
87	¹⁹⁹Fr