Tungsten-178

Properties and data of the isotope ¹⁷⁸W.

Content

General data

Name of the isotope:Tungsten-178; W-178Symbol:¹⁷⁸W or 17874WMass number A:178 (= number of nucleons)Atomic number Z:74 (= number of protons)Neutrons N:104Isotopic mass:177.945886(16) u (atomic weight of Tungsten-178)Nuclide mass:177.9052951 u (calculated nuclear mass without electrons)Mass excess:-50.40687 MeVMass defect:1.534317632 u (per nucleus)Nuclear binding energy:1429.2076683 MeV (per nucleus)
8.02925656 MeV (average binding energy per nucleon)Separation energy:S_N = 8.78(3) MeV (first neutron)
S_P = 5.981(15) MeV (first proton)Half-life:21.6(3) dDecay constant λ:3.714137412979 × 10^-7 s^-1Specific activity α:1.263675631306 × 10⁺¹⁵ Bq g^-1
34153.395440716 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:1950

Radioactive Decay

Half-life T_½ = 21.6(3) d respectively 1.866240 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EE	¹⁷⁸Ta	100 %	0.19(5) MeV

Parent Nuclides

Direct parent isotope is: ¹⁷⁸Re.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 104) and isobaric (same nucleon number A = 178) with Tungsten-178. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

OZ	Isotone N = 104	Isobar A = 178
62	¹⁶⁶Sm
63	¹⁶⁷Eu
64	¹⁶⁸Gd
65	¹⁶⁹Tb
66	¹⁷⁰Dy
67	¹⁷¹Ho
68	¹⁷²Er
69	¹⁷³Tm	¹⁷⁸Tm
70	¹⁷⁴Yb	¹⁷⁸Yb
71	¹⁷⁵Lu	¹⁷⁸Lu
72	¹⁷⁶Hf	¹⁷⁸Hf
73	¹⁷⁷Ta	¹⁷⁸Ta
74	¹⁷⁸W	¹⁷⁸W
75	¹⁷⁹Re	¹⁷⁸Re
76	¹⁸⁰Os	¹⁷⁸Os
77	¹⁸¹Ir	¹⁷⁸Ir
78	¹⁸²Pt	¹⁷⁸Pt
79	¹⁸³Au	¹⁷⁸Au
80	¹⁸⁴Hg	¹⁷⁸Hg
81	¹⁸⁵Tl	¹⁷⁸Tl
82	¹⁸⁶Pb	¹⁷⁸Pb
83	¹⁸⁷Bi
84	¹⁸⁸Po