Tungsten-181

Properties and data of the isotope ¹⁸¹W.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

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

General data

Name of the isotope:Tungsten-181; W-181Symbol:¹⁸¹W or 18174WMass number A:181 (= number of nucleons)Atomic number Z:74 (= number of protons)Neutrons N:107Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.4459459459459 (= neutron-proton ratio)Neutron excess (N-Z):33Isotopic mass:180.9482189(16) u (atomic weight of Tungsten-181)Nuclide mass:180.907628 u (calculated nuclear mass without electrons)Mass excess:-48.23378 MeVMass defect:1.55797948 u (per nucleus)Nuclear binding energy:1451.24853774 MeV (per nucleus)
8.01794772 MeV (average binding energy per nucleon)Separation energy:S_N = 6.66902(16) MeV (first neutron)
S_P = 6.5899(23) MeV (first proton)Half-life:121.2(2) dDecay constant λ:6.619254795409 × 10^-8 s^-1Specific activity α:2.214560264764 × 10⁺¹⁴ Bq g^-1
5985.2980128781 Ci g^-1Spin and parity:
(nuclear angular momentum)9/2+Year of discovery:1947

Radioactive Decay

Half-life T_½ = 121.2(2) d respectively 1.0471680 × 10⁷ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
EC	¹⁸¹Ta	100 %	0.2045(20) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸¹Re.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 107) and isobaric (same nucleon number A = 181) with Tungsten-181. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 107	Isobar A = 181
64	¹⁷¹Gd
65	¹⁷²Tb
66	¹⁷³Dy
67	¹⁷⁴Ho
68	¹⁷⁵Er
69	¹⁷⁶Tm
70	¹⁷⁷Yb	¹⁸¹Yb
71	¹⁷⁸Lu	¹⁸¹Lu
72	¹⁷⁹Hf	¹⁸¹Hf
73	¹⁸⁰Ta	¹⁸¹Ta
74	¹⁸¹W	¹⁸¹W
75	¹⁸²Re	¹⁸¹Re
76	¹⁸³Os	¹⁸¹Os
77	¹⁸⁴Ir	¹⁸¹Ir
78	¹⁸⁵Pt	¹⁸¹Pt
79	¹⁸⁶Au	¹⁸¹Au
80	¹⁸⁷Hg	¹⁸¹Hg
81	¹⁸⁸Tl	¹⁸¹Tl
82	¹⁸⁹Pb	¹⁸¹Pb
83	¹⁹⁰Bi
84	¹⁹¹Po
85	¹⁹²At
86	¹⁹³Rn