Isotopes of tungsten

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Naturally occurring tungsten (W) consists of five isotopes whose half-lives are so long that they can be considered stable. All can decay into isotopes of element 72 (hafnium) by alpha emission; ¹⁸⁰W has been observed to have a half life of 1.8 +- 0.2 Ea. The other naturally occurring isotopes have not been observed to decay, constraining their half-lives to be: ¹⁸²W, T_1/2 > 8.3 Ea; ¹⁸⁴W, T_1/2 > 29 Ea; ¹⁸⁵W, T_1/2 > 13 Ea; ¹⁸⁶W, T_1/2 > 27 Ea. ^[1] On average, two alpha decays of ¹⁸⁰W occur in one gram of natural tungsten per year.

27 artificial radioisotopes of tungsten have been characterized, 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 4 meta states, the most stable being ^179mW (t_½ 6.4 minutes).

Standard atomic mass: 183.84(1) u

[edit] Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
nuclide symbol	excitation energy			half-life	nuclear spin	representative isotopic composition (mole fraction)	range of natural variation (mole fraction)
¹⁵⁸W	74	84	157.97456(54)#	1.37(17) ms	0+
^158mW	1889(8) keV			143(19) µs	8+
¹⁵⁹W	74	85	158.97292(43)#	8.2(7) ms	7/2-#
¹⁶⁰W	74	86	159.96848(22)	90(5) ms	0+
¹⁶¹W	74	87	160.96736(21)#	409(16) ms	7/2-#
¹⁶²W	74	88	161.963497(19)	1.36(7) s	0+
¹⁶³W	74	89	162.96252(6)	2.8(2) s	3/2-#
¹⁶⁴W	74	90	163.958954(13)	6.3(2) s	0+
¹⁶⁵W	74	91	164.958280(27)	5.1(5) s	3/2-#
¹⁶⁶W	74	92	165.955027(11)	19.2(6) s	0+
¹⁶⁷W	74	93	166.954816(21)	19.9(5) s	3/2-#
¹⁶⁸W	74	94	167.951808(17)	51(2) s	0+
¹⁶⁹W	74	95	168.951779(17)	76(6) s	(5/2-)
¹⁷⁰W	74	96	169.949228(16)	2.42(4) min	0+
¹⁷¹W	74	97	170.94945(3)	2.38(4) min	(5/2-)
¹⁷²W	74	98	171.94729(3)	6.6(9) min	0+
¹⁷³W	74	99	172.94769(3)	7.6(2) min	5/2-
¹⁷⁴W	74	100	173.94608(3)	33.2(21) min	0+
¹⁷⁵W	74	101	174.94672(3)	35.2(6) min	(1/2-)
¹⁷⁶W	74	102	175.94563(3)	2.5(1) h	0+
¹⁷⁷W	74	103	176.94664(3)	132(2) min	1/2-
¹⁷⁸W	74	104	177.945876(16)	21.6(3) d	0+
¹⁷⁹W	74	105	178.947070(17)	37.05(16) min	(7/2)-
^179m1W	221.926(8) keV			6.40(7) min	(1/2)-
^179m2W	1631.90(8) keV			390(30) ns	(21/2+)
^179m3W	3348.45(16) keV			750(80) ns	(35/2-)
¹⁸⁰W	74	106	179.946704(4)	STABLE [>700E+15 a]	0+	0.0012(1)
^180m1W	1529.04(3) keV			5.47(9) ms	8-
^180m2W	3264.56(21) keV			2.33(19) µs	14-
¹⁸¹W	74	107	180.948197(5)	121.2(2) d	9/2+
¹⁸²W	74	108	181.9482042(9)	STABLE [>170E+18 a]	0+	0.2650(16)
¹⁸³W	74	109	182.9502230(9)	STABLE [>80E+18 a]	1/2-	0.1431(4)
^183mW	309.493(3) keV			5.2(3) s	11/2+
¹⁸⁴W	74	110	183.9509312(9)	STABLE [>180E+18 a]	0+	0.3064(2)
¹⁸⁵W	74	111	184.9534193(10)	75.1(3) d	3/2-
^185mW	197.43(5) keV			1.597(4) min	11/2+
¹⁸⁶W	74	112	185.9543641(19)	STABLE [>4.1E+18 a]	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	3/2-
¹⁸⁸W	74	114	187.958489(4)	69.78(5) d	0+
¹⁸⁹W	74	115	188.96191(21)	11.6(3) min	(3/2-)
¹⁹⁰W	74	116	189.96318(18)	30.0(15) min	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+

[edit] Notes

Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

[edit] References

^ National Nuclear Data Center table of nuclides, http://www.nndc.bnl.gov/chart/

Isotope masses from Ame2003 Atomic Mass Evaluation by G. Audi, A.H. Wapstra, C. Thibault, J. Blachot and O. Bersillon in Nuclear Physics A729 (2003).
Isotopic compositions and standard atomic masses from Atomic weights of the elements. Review 2000 (IUPAC Technical Report). Pure Appl. Chem. Vol. 75, No. 6, pp. 683-800, (2003) and Atomic Weights Revised (2005).
Half-life, spin, and isomer data selected from these sources. Editing notes on this article's talk page.
- Audi, Bersillon, Blachot, Wapstra. The Nubase2003 evaluation of nuclear and decay properties, Nuc. Phys. A 729, pp. 3-128 (2003).
- National Nuclear Data Center, Brookhaven National Laboratory. Information extracted from the NuDat 2.1 database (retrieved Sept. 2005).
- David R. Lide (ed.), Norman E. Holden in CRC Handbook of Chemistry and Physics, 85th Edition, online version. CRC Press. Boca Raton, Florida (2005). Section 11, Table of the Isotopes.