Neptunium Isotopic Data

 

 

 

Isotope

 

Isotopic Mass

amu

 

% Abundance

 

T1/2

 

T1/2

Units

 

Mass Excess

KeV

 

Binding Energy

Per Nucleon

KeV

 

Decay

Mode

 

Branching

Ratio

225Np

225.033914 (77)

 

3

ms

31,591 (72)

7,607.5 (3.2)

A

100

226Np

226.035145 (95)

 

35

ms

32,738 (88)

7,605 (0)

A

100

227Np

227.034957 (78)

 

510

ms

32,562 (73)

7,607.4 (3.2)

A~100

 

228Np

228.03618 (21)

 

61.4

s

33,700 (200)

7,604 (1)

EC

60 7

229Np

229.036264 (93)

 

4

m

33,780 (87)

7,606.1 (3.8)

A>50

 

230Np

230.037828 (55)

 

4.6

m

35,236 (51)

7,601.8 (2.2)

B+ LE 97

 

231Np

231.038245 (54)

 

48.8

m

35,625 (51)

7,602.1 (2.2)

B+

98 1

232Np

232.04011 (11)

 

14.7

m

37,360 (100)

7,597 (0)

B+~100

 

233Np

233.040741 (55)

 

36.2

m

37,950 (51)

7,596.2 (2.2)

B+~100

 

234Np

234.0428950 (91)

 

4.4

d

39,956.5 (8.5)

7,589.63 (3.6)

B+

100

235Np

235.0440633 (21)

 

396.1

d

41,044.7 (2)

7,587.049 (8)

EC~100

 

236Np

236.046570 (54)

 

154

ky

43,379 (50)

7,579.2 (2.1)

EC

87.3 5

237Np

237.0481734 (20)

 

2.144

My

44,873.3 (1.8)

7,574.982 (8)

A

100

238Np

238.0509464 (20)

 

2.117

d

47,456.3 (1.8)

7,566.214 (8)

B-

100

239Np

239.0529390 (22)

 

2.356

d

49,312.4 (2.1)

7,560.561 (9)

B-

100

240Np

240.056162 (16)

 

61.9

m

52,315 (15)

7,550.18 (6.3)

B-

100

241Np

241.058252 (76)

 

13.9

m

54,262 (71)

7,544.3 (2.9)

B-

100

242Np

242.06164 (21)

 

2.2

m

57,420 (200)

7,533.4 (8.3)

B-

100

243Np

243.064279 (34)

 

1.85

m

59,875 (32)

7,525 (0)

B-

100

244Np

244.06785 (32)

 

2.29

m

63,200 (300)

7,514 (1)

B-

236mNp

236.046570 (54)

 

22.5

h

43,379 (50)

7,579.2 (2.1)

EC

52 1

238mNp

238.0509464 (20)

 

112

ns

47,456.3 (1.8)

7,566.214 (8)

SF~100

 

240mNp

240.056162 (16)

 

7.22

m

52,315 (15)

7,550.18 (6.3)

B-~100

 

242mNp

242.06164 (21)

 

5.5

m

57,420 (200)

7,533.4 (8.3)

B-

100

229mNp

229.036264 (93)

 

 

 

33,780 (87)

7,606.1 (3.8)

0

 

230mNp

230.037828 (55)

 

 

 

35,236 (51)

7,601.8 (2.2)

0

 

231mNp

231.038245 (54)

 

 

 

35,625 (51)

7,602.1 (2.2)

0

 

233mNp

233.040741 (55)

 

 

 

37,950 (51)

7,596.2 (2.2)

0

 

236m1Np

236.046570 (54)

 

 

 

43,379 (50)

7,579.2 (2.1)

0

 

243mNp

243.064279 (34)

 

 

 

59,875 (32)

7,525 (0)

0

 

Data Source: ENSDF March 2005

©Radiochemistry Society 2005