Gold-200m

Properties and data of the isotope ²⁰⁰Au.

Content

General data

Name of the isotope:Gold-200m; Au-200mSymbol:²⁰⁰Au or 20079AuMass number A:200 (= number of nucleons)Atomic number Z:79 (= number of protons)Neutrons N:121Isotopic mass:199.970757(29) u (atomic weight of Gold-200m)
Excitation energy: 962(88) keVNuclide mass:199.9274239 u (calculated nuclear mass without electrons)Mass excess:-27.23968 MeVMass defect:1.695875364 u (per nucleus)Nuclear binding energy:1579.69772631 MeV (per nucleus)
7.89848863 MeV (average binding energy per nucleon)Half-life:18.7(5) hDecay constant λ:1.029630392988 × 10^-5 s^-1Specific activity α:3.115868974999 × 10⁺¹⁶ Bq g^-1
842126.74999995 Ci g^-1Spin and parity:
(nuclear angular momentum)12-

Radioactive Decay

Half-life T_½ = 18.7(5) h (hours) respectively 6.7320 × 10⁴ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	²⁰⁰Hg	84(1) %
Iso	²⁰⁰Au	16(1) %

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
²⁰⁰Au		48.4(3) min	(1-)

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 121) and isobaric (same nucleon number A = 200) with Gold-200m. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 121	Isobar A = 200
73	¹⁹⁴Ta
74	¹⁹⁵W
75	¹⁹⁶Re
76	¹⁹⁷Os	²⁰⁰Os
77	¹⁹⁸Ir	²⁰⁰Ir
78	¹⁹⁹Pt	²⁰⁰Pt
79	²⁰⁰Au	²⁰⁰Au
80	²⁰¹Hg	²⁰⁰Hg
81	²⁰²Tl	²⁰⁰Tl
82	²⁰³Pb	²⁰⁰Pb
83	²⁰⁴Bi	²⁰⁰Bi
84	²⁰⁵Po	²⁰⁰Po
85	²⁰⁶At	²⁰⁰At
86	²⁰⁷Rn	²⁰⁰Rn
87	²⁰⁸Fr	²⁰⁰Fr
88	²⁰⁹Ra
89	²¹⁰Ac
90	²¹¹Th
91	²¹²Pa