Krypton-91

Properties and data of the isotope ⁹¹Kr.

Content

General data

Name of the isotope:Krypton-91; Kr-91Symbol:⁹¹Kr or 9136KrMass number A:91 (= number of nucleons)Atomic number Z:36 (= number of protons)Neutrons N:55Isotopic mass:90.9238063(24) u (atomic weight of Krypton-91)Nuclide mass:90.9040582 u (calculated nuclear mass without electrons)Mass excess:-70.97397 MeVMass defect:0.83446523200001 u (per nucleus)Nuclear binding energy:777.29935682 MeV (per nucleus)
8.54175117 MeV (average binding energy per nucleon)Separation energy:S_N = 4.0860(29) MeV (first neutron)
S_P = 14.263(4) MeV (first proton)Half-life:8.57(4) sDecay constant λ:0.080880651173856 s^-1Specific activity α:5.411940824581 × 10⁺²⁰ Bq g^-1
14626867093.465 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2(+)Magnetic dipole moment:μ(μ_N) = - 0.583(2)Quadrupole moment Q:+ 0.30(3) barn (100 fm²)Nuclear g-factor:g_l = -0.2332Charge radius:4.2543(81) femtometer fmYear of discovery:1951

Radioactive Decay

Half-life T_½ = 8.57(4) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁹¹Rb	100 %	6.771(8) MeV

Parent Nuclides

Direct parent isotopes are: ⁹¹Br, ⁹²Br.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 55) and isobaric (same nucleon number A = 91) with Krypton-91. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 55	Isobar A = 91
30	⁸⁵Zn
31	⁸⁶Ga
32	⁸⁷Ge
33	⁸⁸As	⁹¹As
34	⁸⁹Se	⁹¹Se
35	⁹⁰Br	⁹¹Br
36	⁹¹Kr	⁹¹Kr
37	⁹²Rb	⁹¹Rb
38	⁹³Sr	⁹¹Sr
39	⁹⁴Y	⁹¹Y
40	⁹⁵Zr	⁹¹Zr
41	⁹⁶Nb	⁹¹Nb
42	⁹⁷Mo	⁹¹Mo
43	⁹⁸Tc	⁹¹Tc
44	⁹⁹Ru	⁹¹Ru
45	¹⁰⁰Rh	⁹¹Rh
46	¹⁰¹Pd	⁹¹Pd
47	¹⁰²Ag
48	¹⁰³Cd
49	¹⁰⁴In
50	¹⁰⁵Sn
51	¹⁰⁶Sb
52	¹⁰⁷Te
53	¹⁰⁸I
54	¹⁰⁹Xe