Strontium-78

Properties and data of the isotope ⁷⁸Sr.

Contents

General data

Name of the isotope:Strontium-78; Sr-78Symbol:⁷⁸Sr or 7838SrMass number A:78 (= number of nucleons)Atomic number Z:38 (= number of protons)Neutrons N:40Isotopic mass:77.932180(8) u (atomic weight of Strontium-78)Nuclide mass:77.9113348 u (calculated nuclear mass without electrons)Mass excess:-63.17392 MeVMass defect:0.71176785599999 u (per nucleus)Nuclear binding energy:663.00748726 MeV (per nucleus)
8.50009599 MeV (average binding energy per nucleon)Separation energy:S_N = 13.442(11) MeV (first neutron)
S_P = 5.632(8) MeV (first proton)Half-life:160(8) sDecay constant λ:0.0043321698784997 s^-1Specific activity α:3.388173667207 × 10⁺¹⁹ Bq g^-1
915722612.75886 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Charge radius:4.2561(40) femtometer fmMirror nucleus:Zirconium-78Year of discovery:1982

Radioactive Decay

Half-life T_½ = 160(8) s respectively 1.60 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC/β⁺	⁷⁸Rb	100 %	3.761(8) MeV

Parent Nuclides

Direct parent isotope is: ⁷⁸Y.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 40) and isobaric (same nucleon number A = 78) with Strontium-78. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 40	Isobar A = 78
21	⁶¹Sc
22	⁶²Ti
23	⁶³V
24	⁶⁴Cr
25	⁶⁵Mn
26	⁶⁶Fe
27	⁶⁷Co
28	⁶⁸Ni	⁷⁸Ni
29	⁶⁹Cu	⁷⁸Cu
30	⁷⁰Zn	⁷⁸Zn
31	⁷¹Ga	⁷⁸Ga
32	⁷²Ge	⁷⁸Ge
33	⁷³As	⁷⁸As
34	⁷⁴Se	⁷⁸Se
35	⁷⁵Br	⁷⁸Br
36	⁷⁶Kr	⁷⁸Kr
37	⁷⁷Rb	⁷⁸Rb
38	⁷⁸Sr	⁷⁸Sr
39	⁷⁹Y	⁷⁸Y
40	⁸⁰Zr	⁷⁸Zr
41	⁸¹Nb
42	⁸²Mo