Zinc-81

Properties and data of the isotope ⁸¹Zn.

Content

General data

Name of the isotope:Zinc-81; Zn-81Symbol:⁸¹Zn or 8130ZnMass number A:81 (= number of nucleons)Atomic number Z:30 (= number of protons)Neutrons N:51Isotopic mass:80.950403(5) u (atomic weight of Zinc-81)Nuclide mass:80.9339461 u (calculated nuclear mass without electrons)Mass excess:-46.19931 MeVMass defect:0.72625867600001 u (per nucleus)Nuclear binding energy:676.50559914 MeV (per nucleus)
8.35192098 MeV (average binding energy per nucleon)Separation energy:S_N = 2.622(6) MeV (first neutron)
S_P = 17.29(40) MeV (first proton)Half-life:0.32(5) sDecay constant λ:2.1660849392498 s^-1Specific activity α:1.630558577343 × 10⁺²² Bq g^-1
440691507390.19 Ci g^-1Spin and parity:
(nuclear angular momentum)(5/2+)Year of discovery:1991

Radioactive Decay

Half-life T_½ = 0.32(5) s respectively 3.2 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	⁸¹Ga	92.5 %	11.428(6) MeV
β^-, n	⁸⁰Ga	7.5 %	4.953(6) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 51) and isobaric (same nucleon number A = 81) with Zinc-81. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 51	Isobar A = 81
28	⁷⁹Ni
29	⁸⁰Cu	⁸¹Cu
30	⁸¹Zn	⁸¹Zn
31	⁸²Ga	⁸¹Ga
32	⁸³Ge	⁸¹Ge
33	⁸⁴As	⁸¹As
34	⁸⁵Se	⁸¹Se
35	⁸⁶Br	⁸¹Br
36	⁸⁷Kr	⁸¹Kr
37	⁸⁸Rb	⁸¹Rb
38	⁸⁹Sr	⁸¹Sr
39	⁹⁰Y	⁸¹Y
40	⁹¹Zr	⁸¹Zr
41	⁹²Nb	⁸¹Nb
42	⁹³Mo	⁸¹Mo
43	⁹⁴Tc
44	⁹⁵Ru
45	⁹⁶Rh
46	⁹⁷Pd
47	⁹⁸Ag
48	⁹⁹Cd
49	¹⁰⁰In
50	¹⁰¹Sn