Tungsten-156

Properties and data of the isotope ¹⁵⁶W.

Contents

General Data

Radioactive Decay

Parent Nuclides

Isotones und Isobares

Literature

Tungsten-156 is a radioisotope of the chemical element tungsten, which has 82 neutrons in its atomic nucleus in addition to the element-specific 74 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 156. The very short-lived, only artificially produced, unstable and thus radioactive nuclide has no practical significance; the study of ¹⁵⁶W is exclusively for academic purposes.

The nuclide was first described in 2023 as an α-decay product of the artificially produced isotope Osmium-160 (as well as Os-160m) and the half-life of ¹⁵⁶W was determined to be 157+57-34 ms. Tungsten-156 undergoes β⁺-decay to Tantalum-156.

General data

Name of the isotope:Tungsten-156; W-156Symbol:¹⁵⁶W or 15674WMass number A:156 (= number of nucleons)Atomic number Z:74 (= number of protons)Neutrons N:82Isotopic mass:156 u (atomic weight of Tungsten-156)Nuclide mass:155.9594091 u (calculated nuclear mass without electrons)Mass excess:0 MeVMass defect:1.28957548 u (per nucleus)Nuclear binding energy:1201.23182217 MeV (per nucleus)
7.70020399 MeV (average binding energy per nucleon)Separation energy:
S_P = 0.9(5) MeV (first proton)Half-life:157 msDecay constant λ:4.4149501946493 s^-1Specific activity α:1.704323843704 × 10⁺²² Bq g^-1
460628065865.97 Ci g^-1Spin and parity:
(nuclear angular momentum)0+Year of discovery:2023

Radioactive Decay

Half-life T_½ = 157 ms respectively 1.57 × 10^-1 seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β⁺	¹⁵⁶Ta	100 %

Parent Nuclides

Direct parent isotopes are: ¹⁶⁰Os, ^160mOs.

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 82) and isobaric (same nucleon number A = 156) with Tungsten-156. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 82	Isobar A = 156
45	¹²⁷Rh
46	¹²⁸Pd
47	¹²⁹Ag
48	¹³⁰Cd
49	¹³¹In
50	¹³²Sn
51	¹³³Sb
52	¹³⁴Te
53	¹³⁵I
54	¹³⁶Xe
55	¹³⁷Cs
56	¹³⁸Ba
57	¹³⁹La	¹⁵⁶La
58	¹⁴⁰Ce	¹⁵⁶Ce
59	¹⁴¹Pr	¹⁵⁶Pr
60	¹⁴²Nd	¹⁵⁶Nd
61	¹⁴³Pm	¹⁵⁶Pm
62	¹⁴⁴Sm	¹⁵⁶Sm
63	¹⁴⁵Eu	¹⁵⁶Eu
64	¹⁴⁶Gd	¹⁵⁶Gd
65	¹⁴⁷Tb	¹⁵⁶Tb
66	¹⁴⁸Dy	¹⁵⁶Dy
67	¹⁴⁹Ho	¹⁵⁶Ho
68	¹⁵⁰Er	¹⁵⁶Er
69	¹⁵¹Tm	¹⁵⁶Tm
70	¹⁵²Yb	¹⁵⁶Yb
71	¹⁵³Lu	¹⁵⁶Lu
72	¹⁵⁴Hf	¹⁵⁶Hf
73	¹⁵⁵Ta	¹⁵⁶Ta
74	¹⁵⁶W	¹⁵⁶W