Gold-204

Properties and data of the isotope ²⁰⁴Au.

Content

General data

Name of the isotope:Gold-204; Au-204Symbol:²⁰⁴Au or 20479AuMass number A:204 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:125Isotopic mass:203.97783(21) u (atomic weight of Gold-204)Nuclide mass:203.9344969 u (calculated nuclear mass without electrons)Mass excess:-20.74996 MeVMass defect:1.723568028 u (per nucleus)Nuclear binding energy:1605.49327667 MeV (per nucleus)
7.87006508 MeV (average binding energy per nucleon)Separation energy:S_N = 5.58(20) MeV (first neutron)
S_P = 8.31(28) MeV (first proton)Half-life:39.8(9) sDecay constant λ:0.017415758305526 s^-1Specific activity α:5.166509837364 × 10⁺¹⁹ Bq g^-1
1396354010.0984 Ci g^-1Spin and parity:
(nuclear angular momentum)(2-)Year of discovery:1972

Radioactive Decay

Half-life T_½ = 39.8(9) s respectively 3.98 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁰⁴Hg	100 %	4.04(20) MeV

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 125) and isobaric (same nucleon number A = 204) with Gold-204. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 125	Isobar A = 204
76	²⁰¹Os
77	²⁰²Ir	²⁰⁴Ir
78	²⁰³Pt	²⁰⁴Pt
79	²⁰⁴Au	²⁰⁴Au
80	²⁰⁵Hg	²⁰⁴Hg
81	²⁰⁶Tl	²⁰⁴Tl
82	²⁰⁷Pb	²⁰⁴Pb
83	²⁰⁸Bi	²⁰⁴Bi
84	²⁰⁹Po	²⁰⁴Po
85	²¹⁰At	²⁰⁴At
86	²¹¹Rn	²⁰⁴Rn
87	²¹²Fr	²⁰⁴Fr
88	²¹³Ra	²⁰⁴Ra
89	²¹⁴Ac	²⁰⁴Ac
90	²¹⁵Th
91	²¹⁶Pa
92	²¹⁷U