Zirconium-81

Properties and data of the isotope ⁸¹Zr.

Content

General data

Name of the isotope:Zirconium-81; Zr-81Symbol:⁸¹Zr or 8140ZrMass number A:81 (= number of nucleons)Atomic number Z:40 (= number of protons)Neutrons N:41Isotopic mass:80.93831(10) u (atomic weight of Zirconium-81)Nuclide mass:80.9163678 u (calculated nuclear mass without electrons)Mass excess:-57.46386 MeVMass defect:0.729952836 u (per nucleus)Nuclear binding energy:679.94668702 MeV (per nucleus)
8.39440354 MeV (average binding energy per nucleon)Separation energy:S_N = 11.17(31) MeV (first neutron)
S_P = 3.60(9) MeV (first proton)Half-life:5.5(4) sDecay constant λ:0.12602676010181 s^-1Specific activity α:9.486886268181 × 10⁺²⁰ Bq g^-1
25640233157.248 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2-)Mirror nucleus:Niobium-81Year of discovery:1997

Radioactive Decay

Half-life T_½ = 5.5(4) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	⁸¹Y	98.8 %	8.25(9) MeV
EE, p ?	⁸⁰Sr	0.12(2) %

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 41) and isobaric (same nucleon number A = 81) with Zirconium-81. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 41	Isobar A = 81
22	⁶³Ti
23	⁶⁴V
24	⁶⁵Cr
25	⁶⁶Mn
26	⁶⁷Fe
27	⁶⁸Co
28	⁶⁹Ni
29	⁷⁰Cu	⁸¹Cu
30	⁷¹Zn	⁸¹Zn
31	⁷²Ga	⁸¹Ga
32	⁷³Ge	⁸¹Ge
33	⁷⁴As	⁸¹As
34	⁷⁵Se	⁸¹Se
35	⁷⁶Br	⁸¹Br
36	⁷⁷Kr	⁸¹Kr
37	⁷⁸Rb	⁸¹Rb
38	⁷⁹Sr	⁸¹Sr
39	⁸⁰Y	⁸¹Y
40	⁸¹Zr	⁸¹Zr
41	⁸²Nb	⁸¹Nb
42	⁸³Mo	⁸¹Mo
44	⁸⁵Ru