Gold-181

Properties and data of the isotope ¹⁸¹Au.

Content

General data

Name of the isotope:Gold-181; Au-181Symbol:¹⁸¹Au or 18179AuMass number A:181 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:102Isotopic mass:180.970079(21) u (atomic weight of Gold-181)Nuclide mass:180.9267459 u (calculated nuclear mass without electrons)Mass excess:-27.87123 MeVMass defect:1.53191996 u (per nucleus)Nuclear binding energy:1426.97425122 MeV (per nucleus)
7.88383564 MeV (average binding energy per nucleon)Separation energy:S_N = 10.317(21) MeV (first neutron)
S_P = 0.724(23) MeV (first proton)Half-life:13.7(14) sDecay constant λ:0.050594684712405 s^-1Specific activity α:1.692712878345 × 10⁺²⁰ Bq g^-1
4574899671.2041 Ci g^-1Spin and parity:
(nuclear angular momentum)(3/2-)Year of discovery:1968

Radioactive Decay

Half-life T_½ = 13.7(14) s respectively 1.37 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁷⁷Ir	2.7(5) %	5.7514(29) MeV
EE/β⁺	¹⁸¹Pt	97.3(5) %	6.510(24) MeV

Parent Nuclides

Direct parent isotopes are: ¹⁸⁵Tl, ¹⁸¹Hg.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 102) and isobaric (same nucleon number A = 181) with Gold-181. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 102	Isobar A = 181
60	¹⁶²Nd
61	¹⁶³Pm
62	¹⁶⁴Sm
63	¹⁶⁵Eu
64	¹⁶⁶Gd
65	¹⁶⁷Tb
66	¹⁶⁸Dy
67	¹⁶⁹Ho
68	¹⁷⁰Er
69	¹⁷¹Tm
70	¹⁷²Yb	¹⁸¹Yb
71	¹⁷³Lu	¹⁸¹Lu
72	¹⁷⁴Hf	¹⁸¹Hf
73	¹⁷⁵Ta	¹⁸¹Ta
74	¹⁷⁶W	¹⁸¹W
75	¹⁷⁷Re	¹⁸¹Re
76	¹⁷⁸Os	¹⁸¹Os
77	¹⁷⁹Ir	¹⁸¹Ir
78	¹⁸⁰Pt	¹⁸¹Pt
79	¹⁸¹Au	¹⁸¹Au
80	¹⁸²Hg	¹⁸¹Hg
81	¹⁸³Tl	¹⁸¹Tl
82	¹⁸⁴Pb	¹⁸¹Pb
83	¹⁸⁵Bi
84	¹⁸⁶Po