Gold-189

Properties and data of the isotope ¹⁸⁹Au.

Content

General data

Name of the isotope:Gold-189; Au-189Symbol:¹⁸⁹Au or 18979AuMass number A:189 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:110Isotopic mass:188.963948(22) u (atomic weight of Gold-189)Nuclide mass:188.9206149 u (calculated nuclear mass without electrons)Mass excess:-33.58222 MeVMass defect:1.607370288 u (per nucleus)Nuclear binding energy:1497.25577905 MeV (per nucleus)
7.92198825 MeV (average binding energy per nucleon)Separation energy:S_N = 9.282(20) MeV (first neutron)
S_P = 3.050(20) MeV (first proton)Half-life:28.7(3) minDecay constant λ:0.00040252449509869 s^-1Specific activity α:1.289393196308 × 10⁺¹⁸ Bq g^-1
34848464.765084 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2+Magnetic dipole moment:μ(μ_N) = + 0.494(14)Nuclear g-factor:g_l = 0.988Charge radius:5.4084(52) femtometer fmYear of discovery:1955

Radioactive Decay

Half-life T_½ = 28.7(3) min (minutes) respectively 1.722 × 10³ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE/β⁺	¹⁸⁹Pt	100 %	2.887(22) MeV
α	¹⁸⁵Ir	trace	4.33(3) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸⁹Hg.

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
^189m1Au	247.23(16) keV	4.59(11) min	11/2-
^189m2Au	325.12(16) keV	190(15) ns	9/2-
^189m3Au	2554.8(8) keV	242(10) ns	(31/2+)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 110) and isobaric (same nucleon number A = 189) with Gold-189. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 110	Isobar A = 189
69	¹⁷⁹Tm
70	¹⁸⁰Yb
71	¹⁸¹Lu
72	¹⁸²Hf	¹⁸⁹Hf
73	¹⁸³Ta	¹⁸⁹Ta
74	¹⁸⁴W	¹⁸⁹W
75	¹⁸⁵Re	¹⁸⁹Re
76	¹⁸⁶Os	¹⁸⁹Os
77	¹⁸⁷Ir	¹⁸⁹Ir
78	¹⁸⁸Pt	¹⁸⁹Pt
79	¹⁸⁹Au	¹⁸⁹Au
80	¹⁹⁰Hg	¹⁸⁹Hg
81	¹⁹¹Tl	¹⁸⁹Tl
82	¹⁹²Pb	¹⁸⁹Pb
83	¹⁹³Bi	¹⁸⁹Bi
84	¹⁹⁴Po	¹⁸⁹Po
85	¹⁹⁵At
86	¹⁹⁶Rn