Tungsten-185

Properties and data of the isotope ¹⁸⁵W.

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-185; W-185Symbol:¹⁸⁵W or 18574WMass number A:185 (= number of nucleons)Atomic number Z:74 (= number of protons)Neutrons N:111Nucleon pairing (Z - N):even - oddNuclear ratio (N/Z ratio):1.5 (= neutron-proton ratio)Neutron excess (N-Z):37Isotopic mass:184.9534213(8) u (atomic weight of Tungsten-185)Nuclide mass:184.9128304 u (calculated nuclear mass without electrons)Mass excess:-43.38778 MeVMass defect:1.587436744 u (per nucleus)Nuclear binding energy:1478.68780242 MeV (per nucleus)
7.99290704 MeV (average binding energy per nucleon)Separation energy:S_N = 5.75374(5) MeV (first neutron)
S_P = 7.837(26) MeV (first proton)Half-life:75.1(3) dDecay constant λ:1.068247245277 × 10^-7 s^-1Specific activity α:3.496269230599 × 10⁺¹⁴ Bq g^-1
9449.3762989165 Ci g^-1Spin and parity:
(nuclear angular momentum)3/2-Year of discovery:1940

Radioactive Decay

Half-life T_½ = 75.1(3) d respectively 6.48864 × 10⁶ seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
β^-	¹⁸⁵Re	100 %	0.4312(7) MeV

Parent Nuclides

Direct parent isotope is: ¹⁸⁵Ta.

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
^185mW	197.383(23) keV	1.67(3) min	11/2+

Isotones and Isobars

The following table shows the atomic nuclei that are isotonic (same neutron number N = 111) and isobaric (same nucleon number A = 185) with Tungsten-185. Naturally occurring isotopes are marked in green; light green = naturally occurring radionuclides.

Z	Isotone N = 111	Isobar A = 185
70	¹⁸¹Yb	¹⁸⁵Yb
71	¹⁸²Lu	¹⁸⁵Lu
72	¹⁸³Hf	¹⁸⁵Hf
73	¹⁸⁴Ta	¹⁸⁵Ta
74	¹⁸⁵W	¹⁸⁵W
75	¹⁸⁶Re	¹⁸⁵Re
76	¹⁸⁷Os	¹⁸⁵Os
77	¹⁸⁸Ir	¹⁸⁵Ir
78	¹⁸⁹Pt	¹⁸⁵Pt
79	¹⁹⁰Au	¹⁸⁵Au
80	¹⁹¹Hg	¹⁸⁵Hg
81	¹⁹²Tl	¹⁸⁵Tl
82	¹⁹³Pb	¹⁸⁵Pb
83	¹⁹⁴Bi	¹⁸⁵Bi
84	¹⁹⁵Po
85	¹⁹⁶At
86	¹⁹⁷Rn