Isotopes of neptunium

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Neptunium (Np) has no stable isotopes. A standard atomic mass cannot be given.

[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)
	excitation energy
225Np	93	132	225.03391(8)	3# ms [>2 µs]	9/2-#
226Np	93	133	226.03515(10)#	35(10) ms
227Np	93	134	227.03496(8)	510(60) ms	5/2-#
228Np	93	135	228.03618(21)#	61.4(14) s
229Np	93	136	229.03626(9)	4.0(2) min	5/2+#
230Np	93	137	230.03783(6)	4.6(3) min
231Np	93	138	231.03825(5)	48.8(2) min	(5/2)(+#)
232Np	93	139	232.04011(11)#	14.7(3) min	(4+)
233Np	93	140	233.04074(5)	36.2(1) min	(5/2+)
234Np	93	141	234.042895(9)	4.4(1) d	(0+)
235Np	93	142	235.0440633(21)	396.1(12) d	5/2+
236Np	93	143	236.04657(5)	154(6)E+3 a	(6-)
236mNp	60(50) keV			22.5(4) h	1
237Np	93	144	237.0481734(20)	2.144(7)E+6 a	5/2+
238Np	93	145	238.0509464(20)	2.117(2) d	2+
238mNp	2300(200)# keV			112(39) ns
239Np	93	146	239.0529390(22)	2.356(3) d	5/2+
240Np	93	147	240.056162(16)	61.9(2) min	(5+)
240mNp	20(15) keV			7.22(2) min	1(+)
241Np	93	148	241.05825(8)	13.9(2) min	(5/2+)
242Np	93	149	242.06164(21)	2.2(2) min	(1+)
242mNp	0(50)# keV			5.5(1) min	6+#
243Np	93	150	243.06428(3)#	1.85(15) min	(5/2-)
244Np	93	151	244.06785(32)#	2.29(16) min	(7-)

[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

• 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.

Isotopes of uranium	Isotopes of neptunium	Isotopes of plutonium
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