نظائر التنتالوم

التنتالوم الطبيعي (Ta) يتكون من اثنين من النظائر: ^180mTa (0.012%) و¹⁸¹Ta (99.988%). ¹⁸¹Ta هونظير مستقر. ^180mTa (m ترمز إلى حالة metastable) يـُتوَقع حتى يضمحل بثلاث طرق: انتنطق تزامري isomeric transition إلى ground state وهي ¹⁸⁰Ta, beta decay to ¹⁸⁰W, electron capture to ¹⁸⁰Hf. However, any radioactivity of this nuclear isomer was never observed. Only a lower limit on its half life of over years has been set. The ground state of ¹⁸⁰Ta has a half life of onlyثمانية hours.

^180mTa is the only naturally occurring nuclear isomer (excluding radiogenic and cosmogenic short-living nuclides). It is also the rarest primordial isotope in the Universe of any element that has stable isotopes.

Tantalum has been proposed as a "salting" material for nuclear weapons (cobalt is another, better-known salting material). A jacket of ¹⁸¹Ta, irradiated by the intense high-energy neutron flux from an exploding thermonuclear weapon, would transmute into the radioactive isotope ¹⁸²Ta with a half-life of 114.43 days and produce approximately 1.12 MeV of gamma radiation, significantly increasing the radioactivity of the weapon's fallout for several months. Such a weapon is not known to have ever been built, tested, or used.

Standard atomic mass: 180.94788(2) u

الجدول

رمز النيوكليد	Z(پ)	N(ن)	الكتلة النظيرية (u)	نصف العمر	nuclear spin	representative isotopic composition (mole fraction)	نطاق variation الطبيعي (mole fraction)
رمز النيوكليد	طاقة الاستثارة			نصف العمر	nuclear spin	representative isotopic composition (mole fraction)	نطاق variation الطبيعي (mole fraction)
¹⁵⁵Ta	73	82	154.97459(54)#	13(4) µs [12(+4-3) µs]	(11/2-)
¹⁵⁶Ta	73	83	155.97230(43)#	144(24) ms	(2-)
^156mTa	102(7) keV			0.36(4) s	9+
¹⁵⁷Ta	73	84	156.96819(22)	10.1(4) ms	1/2+
^157m1Ta	22(5) keV			4.3(1) ms	11/2-
^157m2Ta	1593(9) keV			1.7(1) ms	(25/2-)
¹⁵⁸Ta	73	85	157.96670(22)#	49(8) ms	(2-)
^158mTa	141(9) keV			36.0(8) ms	(9+)
¹⁵⁹Ta	73	86	158.963018(22)	1.04(9) s	(1/2+)
^159mTa	64(5) keV			514(9) ms	(11/2-)
¹⁶⁰Ta	73	87	159.96149(10)	1.70(20) s	(2#)-
^160mTa	310(90)# keV			1.55(4) s	(9)+
¹⁶¹Ta	73	88	160.95842(6)#	3# s	1/2+#
^161mTa	50(50)# keV			2.89(12) s	11/2-#
¹⁶²Ta	73	89	161.95729(6)	3.57(12) s	3+#
¹⁶³Ta	73	90	162.95433(4)	10.6(18) s	1/2+#
¹⁶⁴Ta	73	91	163.95353(3)	14.2(3) s	(3+)
¹⁶⁵Ta	73	92	164.950773(19)	31.0(15) s	5/2-#
^165mTa	60(30) keV				9/2-#
¹⁶⁶Ta	73	93	165.95051(3)	34.4(5) s	(2)+
¹⁶⁷Ta	73	94	166.94809(3)	1.33(7) min	(3/2+)
¹⁶⁸Ta	73	95	167.94805(3)	2.0(1) min	(2-,3+)
¹⁶⁹Ta	73	96	168.94601(3)	4.9(4) min	(5/2+)
¹⁷⁰Ta	73	97	169.94618(3)	6.76(6) min	(3)(+#)
¹⁷¹Ta	73	98	170.94448(3)	23.3(3) min	(5/2-)
¹⁷²Ta	73	99	171.94490(3)	36.8(3) min	(3+)
¹⁷³Ta	73	100	172.94375(3)	3.14(13) h	5/2-
¹⁷⁴Ta	73	101	173.94445(3)	1.14(8) h	3+
¹⁷⁵Ta	73	102	174.94374(3)	10.5(2) h	7/2+
¹⁷⁶Ta	73	103	175.94486(3)	8.09(5) h	(1)-
^176m1Ta	103.0(10) keV			1.1(1) ms	(+)
^176m2Ta	1372.6(11)+X keV			3.8(4) µs	(14-)
^176m3Ta	2820(50) keV			0.97(7) ms	(20-)
¹⁷⁷Ta	73	104	176.944472(4)	56.56(6) h	7/2+
^177m1Ta	73.36(15) keV			410(7) ns	9/2-
^177m2Ta	186.15(6) keV			3.62(10) µs	5/2-
^177m3Ta	1355.01(19) keV			5.31(25) µs	21/2-
^177m4Ta	4656.3(5) keV			133(4) µs	49/2-
¹⁷⁸Ta	73	105	177.945778(16)	9.31(3) min	1+
^178m1Ta	100(50)# keV			2.36(8) h	(7)-
^178m2Ta	1570(50)# keV			59(3) ms	(15-)
^178m3Ta	3000(50)# keV			290(12) ms	(21-)
¹⁷⁹Ta	73	106	178.9459295(23)	1.82(3) a	7/2+
^179m1Ta	30.7(1) keV			1.42(8) µs	(9/2)-
^179m2Ta	520.23(18) keV			335(45) ns	(1/2)+
^179m3Ta	1252.61(23) keV			322(16) ns	(21/2-)
^179m4Ta	1317.3(4) keV			9.0(2) ms	(25/2+)
^179m5Ta	1327.9(4) keV			1.6(4) µs	(23/2-)
^179m6Ta	2639.3(5) keV			54.1(17) ms	(37/2+)
¹⁸⁰Ta	73	107	179.9474648(24)	8.152(6) h	1+
^180m1Ta	77.1(8) keV			>1.2E+15 a	9-	0.00012(2)
^180m2Ta	1452.40(18) keV			31.2(14) µs	15-
^180m3Ta	3679.0(11) keV			2.0(5) µs	(22-)
^180m4Ta	4171.0+X keV			17(5) µs	(23,24,25)
¹⁸¹Ta	73	108	180.9479958(19)	STABLE	7/2+	0.99988(2)
^181m1Ta	6.238(20) keV			6.05(12) µs	9/2-
^181m2Ta	615.21(3) keV			18(1) µs	1/2+
^181m3Ta	1485(3) keV			25(2) µs	21/2-
^181m4Ta	2230(3) keV			210(20) µs	29/2-
¹⁸²Ta	73	109	181.9501518(19)	114.43(3) d	3-
^182m1Ta	16.263(3) keV			283(3) ms	5+
^182m2Ta	519.572(18) keV			15.84(10) min	10-
¹⁸³Ta	73	110	182.9513726(19)	5.1(1) d	7/2+
^183mTa	73.174(12) keV			107(11) ns	9/2-
¹⁸⁴Ta	73	111	183.954008(28)	8.7(1) h	(5-)
¹⁸⁵Ta	73	112	184.955559(15)	49.4(15) min	(7/2+)#
^185mTa	1308(29) keV			>1 ms	(21/2-)
¹⁸⁶Ta	73	113	185.95855(6)	10.5(3) min	(2-,3-)
^186mTa				1.54(5) min
¹⁸⁷Ta	73	114	186.96053(21)#	2# min [>300 ns]	7/2+#
¹⁸⁸Ta	73	115	187.96370(21)#	20# s [>300 ns]
¹⁸⁹Ta	73	116	188.96583(32)#	3# s [>300 ns]	7/2+#
¹⁹⁰Ta	73	117	189.96923(43)#	0.3# s

هامش

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.

المصادر

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.

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