Germanium-72

Properties and data of the isotope ⁷²Ge.

Contents

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

General data

Name of the isotope:Germanium-72; Ge-72Symbol:⁷²Ge or 7232GeMass number A:72 (= number of nucleons)Atomic number Z:32 (= number of protons)Neutrons N:40Nucleon pairing (Z - N):even - evenNuclear ratio (N/Z ratio):1.25 (= neutron-proton ratio)Neutron excess (N-Z):8Isotopic mass:71.9220758(5) u (atomic weight of Germanium-72)Nuclide mass:71.9045218 u (calculated nuclear mass without electrons)Mass excess:-72.58592 MeVMass defect:0.674921864 u (per nucleus)Nuclear binding energy:628.68566678 MeV (per nucleus)
8.73174537 MeV (average binding energy per nucleon)Separation energy:S_N = 10.7507(8) MeV (first neutron)
S_P = 9.7357(8) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)0+Charge radius:4.0576(13) femtometer fmYear of discovery:1923

Parent Nuclides

Direct parent isotopes are: ⁷²As, ⁷²Ga.

Occurrence

Comparison of the natural Germanium isotopes including isotopic abundance (mole fraction of the isotope mixture in percent):

	Atomic Mass m_a	Quantity	Half-life	Spin
Germanium Isotopic mixture	72.630 u	100 %
Isotope ⁷⁰Ge	69.924249(6) u	20.52(19) %	stable	0+
Isotope ⁷²Ge	71.9220758(5) u	27.45(15) %	stable	0+
Isotope ⁷⁴Ge	73.92117776(9) u	36.52(12) %	stable	0+
Isotope ⁷⁶Ge	75.9214027(2) u	7.75(12) %	1.926(94) × 10²¹ a	0+
Isotope ⁷³Ge	72.92345895(6) u	7.76(8) %	stable	9/2+

Nuclear Isomers

Nuclear isomers or excited states with the activation energy in keV related to the ground state.

Nuclear Isomer	Excitation Energy	Half-life	Spin
^72mGe	691.43(4) keV	444.2(8) ns	0+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 40) and isobaric (same nucleon number A = 72) with Germanium-72. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 40	Isobar A = 72
19	⁵⁹K
21	⁶¹Sc
22	⁶²Ti
23	⁶³V
24	⁶⁴Cr
25	⁶⁵Mn
26	⁶⁶Fe	⁷²Fe
27	⁶⁷Co	⁷²Co
28	⁶⁸Ni	⁷²Ni
29	⁶⁹Cu	⁷²Cu
30	⁷⁰Zn	⁷²Zn
31	⁷¹Ga	⁷²Ga
32	⁷²Ge	⁷²Ge
33	⁷³As	⁷²As
34	⁷⁴Se	⁷²Se
35	⁷⁵Br	⁷²Br
36	⁷⁶Kr	⁷²Kr
37	⁷⁷Rb	⁷²Rb
38	⁷⁸Sr
39	⁷⁹Y
40	⁸⁰Zr
41	⁸¹Nb
42	⁸²Mo