Mercury-185

Properties and data of the isotope ¹⁸⁵Hg.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Mercury-185; Hg-185Symbol:¹⁸⁵Hg or 18580HgMass number A:185 (= number of nucleons)Atomic number Z:80 (= number of protons)Neutrons N:105Isotopic mass:184.971891(15) u (atomic weight of Mercury-185)Nuclide mass:184.9280094 u (calculated nuclear mass without electrons)Mass excess:-26.18336 MeVMass defect:1.56392774 u (per nucleus)Nuclear binding energy:1456.78930624 MeV (per nucleus)
7.87453679 MeV (average binding energy per nucleon)Separation energy:S_N = 7.906(17) MeV (first neutron)
S_P = 3.154(26) MeV (first proton)Half-life:49.1(10) sDecay constant λ:0.014117050520569 s^-1Specific activity α:4.620373193571 × 10⁺¹⁹ Bq g^-1
1248749511.776 Ci g^-1Spin and parity:
(nuclear angular momentum)1/2-Magnetic dipole moment:μ(μ_N) = + 0.508(3)Nuclear g-factor:g_l = 1.016Charge radius:5.4397(31) femtometer fmYear of discovery:1960

Radioactive Decay

Half-life T_½ = 49.1(10) s respectively 4.91 × 10¹ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁸¹Pt	6(1) %	5.773(4) MeV
EC/β⁺	¹⁸⁵Au	94(1) %	5.674(14) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸⁹Pb.

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
^185mHg	99.3(5) keV	21.6(15) s	13/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 105) and isobaric (same nucleon number A = 185) with Mercury-185. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 105	Isobar A = 185
63	¹⁶⁸Eu
64	¹⁶⁹Gd
65	¹⁷⁰Tb
66	¹⁷¹Dy
67	¹⁷²Ho
68	¹⁷³Er
69	¹⁷⁴Tm
70	¹⁷⁵Yb	¹⁸⁵Yb
71	¹⁷⁶Lu	¹⁸⁵Lu
72	¹⁷⁷Hf	¹⁸⁵Hf
73	¹⁷⁸Ta	¹⁸⁵Ta
74	¹⁷⁹W	¹⁸⁵W
75	¹⁸⁰Re	¹⁸⁵Re
76	¹⁸¹Os	¹⁸⁵Os
77	¹⁸²Ir	¹⁸⁵Ir
78	¹⁸³Pt	¹⁸⁵Pt
79	¹⁸⁴Au	¹⁸⁵Au
80	¹⁸⁵Hg	¹⁸⁵Hg
81	¹⁸⁶Tl	¹⁸⁵Tl
82	¹⁸⁷Pb	¹⁸⁵Pb
83	¹⁸⁸Bi	¹⁸⁵Bi
84	¹⁸⁹Po
85	¹⁹⁰At