Tungsten-185m

Properties and data of the isotope ^185mW.

Contents

General data

Name of the isotope:Tungsten-185m; W-185mSymbol:^185mW or 185m74WMass number A:185 (= number of nucleons)Atomic number Z:74 (= number of protons)Neutrons N:111Isotopic mass:184.9534213(8) u (atomic weight of Tungsten-185m)
Excitation energy: 197.383(23) keVNuclide 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)Half-life:1.67(3) minDecay constant λ:0.0069176365325344 s^-1Specific activity α:2.264075087867 × 10⁺¹⁹ Bq g^-1
611912185.91019 Ci g^-1Spin and parity:
(nuclear angular momentum)11/2+

Radioactive Decay

Half-life T_½ = 1.67(3) min (minutes) respectively 1.002 × 10² seconds s.

Decay mode	Daughter	Probability	Decay energy	γ energy (intensity)
Iso	¹⁸⁵W	100 %

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
¹⁸⁵W		75.1(3) d	3/2-

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-185m. 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