Mercury-178

Properties and data of the isotope ¹⁷⁸Hg.

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-178; Hg-178Symbol:¹⁷⁸Hg or 17880HgMass number A:178 (= number of nucleons)Atomic number Z:80 (= number of protons)Neutrons N:98Isotopic mass:177.982484(12) u (atomic weight of Mercury-178)Nuclide mass:177.9386024 u (calculated nuclear mass without electrons)Mass excess:-16.31605 MeVMass defect:1.492680328 u (per nucleus)Nuclear binding energy:1390.42276945 MeV (per nucleus)
7.81136387 MeV (average binding energy per nucleon)Separation energy:S_N = 11.60(8) MeV (first neutron)
S_P = 20.60(15) MeV (first proton)Half-life:266.5(24) msDecay constant λ:2.6009275067915 s^-1Specific activity α:8.849238312080 × 10⁺²¹ Bq g^-1
239168603029.21 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1971

Radioactive Decay

Half-life T_½ = 266.5(24) ms respectively 2.665 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
α	¹⁷⁴Pt	ca. 70 %	6.577(3) MeV
EC/β⁺	¹⁷⁸Au	ca. 30 %	5.988(15) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸²Pb.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 98) and isobaric (same nucleon number A = 178) with Mercury-178. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 98	Isobar A = 178
57	¹⁵⁵La
58	¹⁵⁶Ce
59	¹⁵⁷Pr
60	¹⁵⁸Nd
61	¹⁵⁹Pm
62	¹⁶⁰Sm
63	¹⁶¹Eu
64	¹⁶²Gd
65	¹⁶³Tb
66	¹⁶⁴Dy
67	¹⁶⁵Ho
68	¹⁶⁶Er
69	¹⁶⁷Tm	¹⁷⁸Tm
70	¹⁶⁸Yb	¹⁷⁸Yb
71	¹⁶⁹Lu	¹⁷⁸Lu
72	¹⁷⁰Hf	¹⁷⁸Hf
73	¹⁷¹Ta	¹⁷⁸Ta
74	¹⁷²W	¹⁷⁸W
75	¹⁷³Re	¹⁷⁸Re
76	¹⁷⁴Os	¹⁷⁸Os
77	¹⁷⁵Ir	¹⁷⁸Ir
78	¹⁷⁶Pt	¹⁷⁸Pt
79	¹⁷⁷Au	¹⁷⁸Au
80	¹⁷⁸Hg	¹⁷⁸Hg
81	¹⁷⁹Tl	¹⁷⁸Tl
82	¹⁸⁰Pb	¹⁷⁸Pb