Isotopes of tungsten

Isotopes of tungsten (₇₄W)

Main isotopes Decay abun­dance half-life (t1/2) mode pro­duct ^180W 0.120% 1.8×10^18 y α ^176Hf ^181W synth 121.2 d ε ^181Ta ^182W 26.5% stable ^183W 14.3% stable ^184W 30.6% stable ^185W synth 75.1 d β^− ^185Re ^186W 28.4% stable ^188W synth 69.78 d β^− ^188Re
Standard atomic weight Ar°(W)
	183.84±0.01[1] 183.84±0.01 (abridged)[2]

Naturally occurring tungsten (₇₄W) consists of five isotopes. Four are considered stable (^182W, ^183W, ^184W, and ^186W) and one is slightly radioactive, ^180W, with an extremely long half-life of 1.8 ± 0.2 exayears (10^18 years). On average, two alpha decays of ^180W occur per gram of natural tungsten per year, so for most practical purposes, ^180W can be considered stable. Theoretically, all five can decay into isotopes of element 72 (hafnium) by alpha emission, but only ^180W has been observed to do so. The other naturally occurring isotopes have not been observed to decay (they are observationally stable), and lower bounds for their half-lives have been established:

^182W, t_1/2 > 7.7×10^21 years

^183W, t_1/2 > 4.1×10^21 years

^184W, t_1/2 > 8.9×10^21 years

^186W, t_1/2 > 8.2×10^21 years

Thirty-four artificial radioisotopes of tungsten have been characterized with mass numbers ranging from 156 to 194, the most stable of which are ^181W with a half-life of 121.2 days, ^185W with a half-life of 75.1 days, ^188W with a half-life of 69.4 days and ^178W with a half-life of 21.6 days. All of the remaining radioactive isotopes have half-lives of less than 24 hours, and most of these have half-lives that are less than 8 minutes. Tungsten also has twelve known meta states, the most stable being ^179m1W (t_1/2 6.4 minutes).

List of isotopes

Nuclide [n 1]	Z	N	Isotopic mass (Da) [n 2][n 3]	Half-life [n 4][n 5]	Decay mode [n 6]	Daughter isotope [n 7][n 8]	Spin and parity [n 9][n 5]	Natural abundance (mole fraction)
	Excitation energy							Normal proportion	Range of variation
^156W[3]	74	82		157+57 −34 ms	β^+	^156Ta	0+
^157W[4]	74	83		275(40) ms	β^+	^157Ta	(7/2−)
^158W	74	84	157.97456(54)#	1.37(17) ms	α	^154Hf	0+
^158mW	1889(8) keV			143(19) μs	α	^154Hf	8+
^159W	74	85	158.97292(43)#	8.2(7) ms	α (82%)	^155Hf	7/2−#
					β^+ (18%)	^159Ta
^160W	74	86	159.96848(22)	90(5) ms	α (87%)	^156Hf	0+
					β^+ (14%)	^160Ta
^161W	74	87	160.96736(21)#	409(16) ms	α (73%)	^157Hf	7/2−#
					β^+ (23%)	^161Ta
^162W	74	88	161.963497(19)	1.36(7) s	β^+ (53%)	^162Ta	0+
					α (47%)	^158Hf
^163W	74	89	162.96252(6)	2.8(2) s	β^+ (59%)	^163Ta	3/2−#
					α (41%)	^159Hf
^164W	74	90	163.958954(13)	6.3(2) s	β^+ (97.4%)	^164Ta	0+
					α (2.6%)	^160Hf
^165W	74	91	164.958280(27)	5.1(5) s	β^+ (99.8%)	^165Ta	3/2−#
					α (.2%)	^161Hf
^166W	74	92	165.955027(11)	19.2(6) s	β^+ (99.96%)	^166Ta	0+
					α (.035%)	^162Hf
^167W	74	93	166.954816(21)	19.9(5) s	β^+ (>99.9%)	^167Ta	3/2−#
					α (<.1%)	^163Hf
^168W	74	94	167.951808(17)	51(2) s	β^+ (99.99%)	^168Ta	0+
					α (.0319%)	^164Hf
^169W	74	95	168.951779(17)	76(6) s	β^+	^169Ta	(5/2−)
^170W	74	96	169.949228(16)	2.42(4) min	β^+(99%)	^170Ta	0+
					α (1%)	^166Hf
^171W	74	97	170.94945(3)	2.38(4) min	β^+	^171Ta	(5/2−)
^172W	74	98	171.94729(3)	6.6(9) min	β^+	^172Ta	0+
^173W	74	99	172.94769(3)	7.6(2) min	β^+	^173Ta	5/2−
^174W	74	100	173.94608(3)	33.2(21) min	β^+	^174Ta	0+
^175W	74	101	174.94672(3)	35.2(6) min	β^+	^175Ta	(1/2−)
^176W	74	102	175.94563(3)	2.5(1) h	EC	^176Ta	0+
^177W	74	103	176.94664(3)	132(2) min	β^+	^177Ta	1/2−
^178W	74	104	177.945876(16)	21.6(3) d	EC	^178Ta	0+
^179W	74	105	178.947070(17)	37.05(16) min	β^+	^179Ta	(7/2)−
^179m1W	221.926(8) keV			6.40(7) min	IT (99.72%)	^179W	(1/2)−
					β^+ (.28%)	^179Ta
^179m2W	1631.90(8) keV			390(30) ns			(21/2+)
^179m3W	3348.45(16) keV			750(80) ns			(35/2−)
^180W[n 10]	74	106	179.946704(4)	1.8(0.2)×10^18 y	α	^176Hf	0+	0.0012(1)
^180m1W	1529.04(3) keV			5.47(9) ms	IT	^180W	8−
^180m2W	3264.56(21) keV			2.33(19) μs			14−
^181W	74	107	180.948197(5)	121.2(2) d	EC	^181Ta	9/2+
^182W	74	108	181.9482042(9)	Observationally Stable[n 11]			0+	0.2650(16)
^183W	74	109	182.9502230(9)	Observationally Stable[n 12]			1/2−	0.1431(4)
^183mW	309.493(3) keV			5.2(3) s	IT	^183W	11/2+
^184W	74	110	183.9509312(9)	Observationally Stable[n 13]			0+	0.3064(2)
^185W	74	111	184.9534193(10)	75.1(3) d	β^−	^185Re	3/2−
^185mW	197.43(5) keV			1.597(4) min	IT	^185W	11/2+
^186W	74	112	185.9543641(19)	Observationally Stable[n 14]			0+	0.2843(19)
^186m1W	1517.2(6) keV			18(1) μs			(7−)
^186m2W	3542.8(21) keV			>3 ms			(16+)
^187W	74	113	186.9571605(19)	23.72(6) h	β^−	^187Re	3/2−
^187mW[5]	~411 keV			1.54(13) μs	IT	^187W	11/2+
^188W	74	114	187.958489(4)	69.78(5) d	β^−	^188Re	0+
^189W	74	115	188.96191(21)	11.6(3) min	β^−	^189Re	(3/2−)
^190W	74	116	189.96318(18)	30.0(15) min	β^−	^190Re	0+
^190mW	2381(5) keV			<3.1 ms			(10−)
^191W	74	117	190.96660(21)#	20# s [>300 ns]			3/2−#
^192W	74	118	191.96817(64)#	10# s [>300 ns]			0+
This table header & footer: view

1. ^mW – Excited nuclear isomer.
2. ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. Bold half-life – nearly stable, half-life longer than age of universe.
5. # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
6. Modes of decay:

   EC:	Electron capture
   IT:	Isomeric transition

7. Bold italics symbol as daughter – Daughter product is nearly stable.
8. Bold symbol as daughter – Daughter product is stable.
9. ( ) spin value – Indicates spin with weak assignment arguments.
10. Primordial radionuclide
11. Believed to undergo α decay to ^178Hf with a half-life over 7.7×10^21 y
12. Believed to undergo α decay to ^179Hf with a half-life over 4.1×10^21 y
13. Believed to undergo α decay to ^180Hf with a half-life over 8.9×10^21 y
14. Believed to undergo α decay to ^182Hf or β^−β^− decay to ^186Os with a half-life over 8.2×10^21 y

References

1. "Standard Atomic Weights: Tungsten". CIAAW. 1991.
2. Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
3. Briscoe, A. D.; Page, R. D.; Uusitalo, J.; et al. (2023). "Decay spectroscopy at the two-proton drip line: Radioactivity of the new nuclides ^160Os and ^156W". Physics Letters B. 47 (138310). doi:10.1016/j.physletb.2023.138310. hdl:10272/23933.
4. Bianco, L.; Page, R. D.; Darby, I. G.; et al. (7 June 2010). "Discovery of ^157W and ^161Os" (PDF). Physics Letters B. 690 (1): 15–18. Bibcode:2010PhLB..690...15B. doi:10.1016/j.physletb.2010.04.056. ISSN 0370-2693. S2CID 117121162. Retrieved 11 June 2023.
5. Chen, J. L.; Watanabe, H.; Walker, P. M.; et al. (2025). "Direct observation of β and γ decay from a high-spin long-lived isomer in ^187Ta". Physical Review C. 111 (014304). arXiv:2501.02848. doi:10.1103/PhysRevC.111.014304.

• Isotope masses from:
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
• Isotopic compositions and standard atomic masses from:
  • de Laeter, John Robert; Böhlke, John Karl; De Bièvre, Paul; Hidaka, Hiroshi; Peiser, H. Steffen; Rosman, Kevin J. R.; Taylor, Philip D. P. (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683–800. doi:10.1351/pac200375060683.
  • Wieser, Michael E. (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051–2066. doi:10.1351/pac200678112051.
• "News & Notices: Standard Atomic Weights Revised". International Union of Pure and Applied Chemistry. 19 October 2005.
• Half-life, spin, and isomer data selected from the following sources.
  • Audi, Georges; Bersillon, Olivier; Blachot, Jean; Wapstra, Aaldert Hendrik (2003), "The NUBASE evaluation of nuclear and decay properties", Nuclear Physics A, 729: 3–128, Bibcode:2003NuPhA.729....3A, doi:10.1016/j.nuclphysa.2003.11.001
  • National Nuclear Data Center. "NuDat 2.x database". Brookhaven National Laboratory.
  • Holden, Norman E. (2004). "11. Table of the Isotopes". In Lide, David R. (ed.). CRC Handbook of Chemistry and Physics (85th ed.). Boca Raton, Florida: CRC Press. ISBN 978-0-8493-0485-9.