Isotopes of neptunium
List of isotopes
Abbreviations: CD: Cluster decay EC: Electron capture IT: Isomeric transition SF: Spontaneous fission Fissile nuclide Most common nuclide

Isotopes of neptunium

Section Title: List of isotopes
Table Section Text: Abbreviations: CD: Cluster decay EC: Electron capture IT: Isomeric transition SF: Spontaneous fission Fissile nuclide Most common nuclide

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)	daughter isotope(s)	nuclear spin and parity

excitation energy

219 Np	93	126	219.03162(9)	0.15(+0.72-0.07) ms	α	215Pa	(9/2−)

223 Np	93	130	223.03285(21)#	2.15(+100-52) µs	α	219Pa	9/2−

224 Np	93	131	224.03422(21)#	38(+26-11) µs	α (83%)	220m1Pa	1-#

α (17%)	220m2Pa

225 Np	93	132	225.03391(8)	6(5) ms	α	221Pa	9/2−#

226 Np	93	133	226.03515(10)#	35(10) ms	α	222Pa

227 Np	93	134	227.03496(8)	510(60) ms	α (99.95%)	223Pa	5/2−#

β+ (.05%)	227U

228 Np	93	135	228.03618(21)#	61.4(14) s	β+ (59%)	228U

α (41%)	224Pa

β+, SF (.012%)	(various)

229 Np	93	136	229.03626(9)	4.0(2) min	α (51%)	225Pa	5/2+#

β+ (49%)	229U

230 Np	93	137	230.03783(6)	4.6(3) min	β+ (97%)	230U

α (3%)	226Pa

231 Np	93	138	231.03825(5)	48.8(2) min	β+ (98%)	231U	(5/2)(+#)

α (2%)	227Pa

232 Np	93	139	232.04011(11)#	14.7(3) min	β+ (99.99%)	232U	(4+)

α (.003%)	228Pa

233 Np	93	140	233.04074(5)	36.2(1) min	β+ (99.99%)	233U	(5/2+)

α (.001%)	229Pa

234 Np	93	141	234.042895(9)	4.4(1) d	β+	234U	(0+)

235 Np	93	142	235.0440633(21)	396.1(12) d	EC	235U	5/2+

α (.0026%)	231Pa

236 Np	93	143	236.04657(5)	1.54(6)×105 y	EC (87.3%)	236U	(6−)

β− (12.5%)	236Pu

α (.16%)	232Pa

236m Np	60(50) keV	22.5(4) h	EC (52%)	236U	1

β− (48%)	236Pu

237 Np	93	144	237.0481734(20)	2.144(7)×106 y	α	233Pa	5/2+

SF (2×10−10%)	(various)

CD (4×10−12%)	207Tl 30Mg

238 Np	93	145	238.0509464(20)	2.117(2) d	β−	238Pu	2+

238m Np	2300(200)# keV	112(39) ns

239 Np	93	146	239.0529390(22)	2.356(3) d	β−	239Pu	5/2+

240 Np	93	147	240.056162(16)	61.9(2) min	β−	240Pu	(5+)

240m Np	20(15) keV	7.22(2) min	β− (99.89%)	240Pu	1(+)

IT (.11%)	240Np

241 Np	93	148	241.05825(8)	13.9(2) min	β−	241Pu	(5/2+)

242 Np	93	149	242.06164(21)	2.2(2) min	β−	242Pu	(1+)

242m Np	0(50)# keV	5.5(1) min	6+#

243 Np	93	150	243.06428(3)#	1.85(15) min	β−	243Pu	(5/2−)

244 Np	93	151	244.06785(32)#	2.29(16) min	β−	244Pu	(7−)

Sentence(s)

This particular isotope of neptunium has a mass of 236.04657 u.

final_sentence: This particular isotope of neptunium has a mass of 236.04657 u.