Gold-178

Properties and data of the isotope ¹⁷⁸Au.

Content

General data

Name of the isotope:Gold-178; Au-178Symbol:¹⁷⁸Au or 17879AuMass number A:178 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:99Isotopic mass:177.976056(11) u (atomic weight of Gold-178)Nuclide mass:177.9327229 u (calculated nuclear mass without electrons)Mass excess:-22.30369 MeVMass defect:1.499948212 u (per nucleus)Nuclear binding energy:1397.19275979 MeV (per nucleus)
7.84939753 MeV (average binding energy per nucleon)Separation energy:S_N = 8.830(15) MeV (first neutron)
S_P = 0.222(18) MeV (first proton)Half-life:2.6(5) sDecay constant λ:0.26659506944613 s^-1Specific activity α:9.070469269882 × 10⁺²⁰ Bq g^-1
24514781810.494 Ci g^-1Spin and parity:
(nuclear angular momentum)Year of discovery:1968

Radioactive Decay

Half-life T_½ = 2.6(5) s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁷⁴Ir	≥ 40 %	6.135(25) MeV
EE/β⁺	¹⁷⁸Pt	≤ 60 %	9.694(14) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸²Tl.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 99) and isobaric (same nucleon number A = 178) with Gold-178. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 99	Isobar A = 178
57	¹⁵⁶La
58	¹⁵⁷Ce
59	¹⁵⁸Pr
60	¹⁵⁹Nd
61	¹⁶⁰Pm
62	¹⁶¹Sm
63	¹⁶²Eu
64	¹⁶³Gd
65	¹⁶⁴Tb
66	¹⁶⁵Dy
67	¹⁶⁶Ho
68	¹⁶⁷Er
69	¹⁶⁸Tm	¹⁷⁸Tm
70	¹⁶⁹Yb	¹⁷⁸Yb
71	¹⁷⁰Lu	¹⁷⁸Lu
72	¹⁷¹Hf	¹⁷⁸Hf
73	¹⁷²Ta	¹⁷⁸Ta
74	¹⁷³W	¹⁷⁸W
75	¹⁷⁴Re	¹⁷⁸Re
76	¹⁷⁵Os	¹⁷⁸Os
77	¹⁷⁶Ir	¹⁷⁸Ir
78	¹⁷⁷Pt	¹⁷⁸Pt
79	¹⁷⁸Au	¹⁷⁸Au
80	¹⁷⁹Hg	¹⁷⁸Hg
81	¹⁸⁰Tl	¹⁷⁸Tl
82	¹⁸¹Pb	¹⁷⁸Pb