Gold-185m

Properties and data of the isotope ¹⁸⁵Au.

Content

General data

Name of the isotope:Gold-185m; Au-185mSymbol:¹⁸⁵Au or 18579AuMass number A:185 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:106Isotopic mass:184.9657989(28) u (atomic weight of Gold-185m)
Excitation energy: +x keVNuclide mass:184.9224658 u (calculated nuclear mass without electrons)Mass excess:-31.85812 MeVMass defect:1.570859724 u (per nucleus)Nuclear binding energy:1463.24640775 MeV (per nucleus)
7.90944004 MeV (average binding energy per nucleon)Half-life:6.8(3) minDecay constant λ:0.0016988901484312 s^-1Specific activity α:5.560302054028 × 10⁺¹⁸ Bq g^-1
150278433.89265 Ci g^-1Spin and parity:
(nuclear angular momentum)5/2-

Radioactive Decay

Half-life T_½ = 6.8(3) min (minutes) respectively 4.08 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁸⁵Au	?
EE/β⁺	¹⁸⁵Pt	< 100 %

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
¹⁸⁵Au		4.25(6) min	5/2-

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 106) and isobaric (same nucleon number A = 185) with Gold-185m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 106	Isobar A = 185
64	¹⁷⁰Gd
65	¹⁷¹Tb
66	¹⁷²Dy
67	¹⁷³Ho
68	¹⁷⁴Er
69	¹⁷⁵Tm
70	¹⁷⁶Yb	¹⁸⁵Yb
71	¹⁷⁷Lu	¹⁸⁵Lu
72	¹⁷⁸Hf	¹⁸⁵Hf
73	¹⁷⁹Ta	¹⁸⁵Ta
74	¹⁸⁰W	¹⁸⁵W
75	¹⁸¹Re	¹⁸⁵Re
76	¹⁸²Os	¹⁸⁵Os
77	¹⁸³Ir	¹⁸⁵Ir
78	¹⁸⁴Pt	¹⁸⁵Pt
79	¹⁸⁵Au	¹⁸⁵Au
80	¹⁸⁶Hg	¹⁸⁵Hg
81	¹⁸⁷Tl	¹⁸⁵Tl
82	¹⁸⁸Pb	¹⁸⁵Pb
83	¹⁸⁹Bi	¹⁸⁵Bi
84	¹⁹⁰Po
85	¹⁹¹At