Gold-197

Properties and data of the isotope ¹⁹⁷Au.

Contents

Gold-197 is the only stable and the only naturally occurring isotope of the monoisotopic element Gold. The atomic nucleus of the nuclide consists of 118 neutrons and the element-specific 79 positively charged protons; The sum of these nucleus building blocks results in the mass number 197.

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

General data

Name of the isotope:Gold-197; Au-197Symbol:¹⁹⁷Au or 19779AuMass number A:197 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:118Nucleon pairing (Z - N):odd - evenNuclear ratio (N/Z ratio):1.4936708860759 (= neutron-proton ratio)Neutron excess (N-Z):39Isotopic mass:196.966569(5) u (atomic weight of Gold-197)Nuclide mass:196.9232359 u (calculated nuclear mass without electrons)Mass excess:-31.14078 MeVMass defect:1.674068616 u (per nucleus)Nuclear binding energy:1559.38487139 MeV (per nucleus)
7.91565925 MeV (average binding energy per nucleon)Separation energy:S_N = 8.0724(29) MeV (first neutron)
S_P = 5.7842(5) MeV (first proton)Half-life:stableSpin and parity:
(nuclear angular momentum)3/2+Magnetic dipole moment:μ(μ_N) = +0.145746Charge radius:5.4371(38) femtometer fmYear of discovery:1935

Parent Nuclides

Direct parent isotopes are: ¹⁹⁷Hg, ¹⁹⁷Pt.

Occurrence

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

	Atomic Mass m_a	Quantity	Half-life	Spin
Gold Isotopic mixture	196.966569 u	100 %
Isotope ¹⁹⁷Au	196.966569(5) u	100 %	stable	3/2+

NMR data

Nuclear magnetic properties and parameters of the NMR active Nuclide ¹⁹⁷Au

Isotope:¹⁹⁷Au-NMRQuantity:100 %Spin:3/2+Nuclearmagnetic moment
μ/μ_N:+0.145746Gyromagnetic ratio γ:0.4692 · 10⁷ rad T^-1 s^-1
0.74675 MHz T^-1Nuclear g-factor:g_l = 0.097164Quadrupole moment Q:+ 0.547(16) barn (100 fm²)Resonance frequency:v₀ = 0.7406 MHz at 1 TRelative Sensitivity:[related to ¹H = 1.000]:
0.00003 (H₀ = const.)
0.0870 (v₀ = const.)
0.0000277 (at natural abundance)
relative receptivity as compared to ¹³C:
0.162 (at natural abundance)Frequency ratio:Ξ(¹⁹⁷Au) = 1.729 % [based on the reference substance]

The atomic nucleus of the nuclide has (not entirely optimal) nuclear magnetic properties and is suitable for ¹⁹⁷Au NMR spectroscopy; In addition, terrestrial gold consists of 100% gold-197. Nevertheless, NMR spectroscopy of gold atoms is an extremely rarely used technique.

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
^197mAu	409.15(8) keV	7.73(6) s	11/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 118) and isobaric (same nucleon number A = 197) with Gold-197. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 118	Isobar A = 197
72	¹⁹⁰Hf
73	¹⁹¹Ta
74	¹⁹²W	¹⁹⁷W
75	¹⁹³Re	¹⁹⁷Re
76	¹⁹⁴Os	¹⁹⁷Os
77	¹⁹⁵Ir	¹⁹⁷Ir
78	¹⁹⁶Pt	¹⁹⁷Pt
79	¹⁹⁷Au	¹⁹⁷Au
80	¹⁹⁸Hg	¹⁹⁷Hg
81	¹⁹⁹Tl	¹⁹⁷Tl
82	²⁰⁰Pb	¹⁹⁷Pb
83	²⁰¹Bi	¹⁹⁷Bi
84	²⁰²Po	¹⁹⁷Po
85	²⁰³At	¹⁹⁷At
86	²⁰⁴Rn	¹⁹⁷Rn
87	²⁰⁵Fr
88	²⁰⁶Ra
89	²⁰⁷Ac
90	²⁰⁸Th