Zinc-55

Properties and data of the isotope ⁵⁵Zn.

Contents

See also: List of individual Zinc isotopes (and general data sources).

General data

Name of the isotope:Zinc-55; Zn-55Symbol:⁵⁵Zn or 5530ZnMass number A:55 (= number of nucleons)Atomic number Z:30 (= number of protons)Neutrons N:25Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):0.83333333333333 (= neutron-proton ratio)Neutron excess (N-Z):-5Isotopic mass:54.98436(43) u (atomic weight of Zinc-55)Nuclide mass:54.9679031 u (calculated nuclear mass without electrons)Mass excess:-14.56857 MeVMass defect:0.46701386 u (per nucleus)Nuclear binding energy:435.02060851 MeV (per nucleus)
7.90946561 MeV (average binding energy per nucleon)Separation energy:S_N = 16.37(56) MeV (first neutron)
S_P = 0.45(56) MeV (first proton)Half-life:20 msDecay constant λ:34.657359027997 s^-1Specific activity α:3.865027738888 × 10⁺²³ Bq g^-1
10446020915916 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-Mirror nucleus:Manganese-55Year of discovery:2001

Radioactive Decay

Half-life T_½ = 20 ms respectively 2.0 × 10^-2 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC p	⁵⁴Ni	91(5) %
β⁺	⁵⁵Cu	?	17.07(43) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 25) and isobaric (same nucleon number A = 55) with Zinc-55. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 25	Isobar A = 55
11	³⁶Na
12	³⁷Mg
13	³⁸Al
14	³⁹Si
15	⁴⁰P
16	⁴¹S
17	⁴²Cl
18	⁴³Ar
19	⁴⁴K	⁵⁵K
20	⁴⁵Ca	⁵⁵Ca
21	⁴⁶Sc	⁵⁵Sc
22	⁴⁷Ti	⁵⁵Ti
23	⁴⁸V	⁵⁵V
24	⁴⁹Cr	⁵⁵Cr
25	⁵⁰Mn	⁵⁵Mn
26	⁵¹Fe	⁵⁵Fe
27	⁵²Co	⁵⁵Co
28	⁵³Ni	⁵⁵Ni
29	⁵⁴Cu	⁵⁵Cu
30	⁵⁵Zn	⁵⁵Zn