Isotopen van francium
Het chemisch element francium (Fr), met een atoommassa van ongeveer 223 u , bezit geen stabiele isotopen en wordt dus geclassificeerd als radioactief element . Van de 34 radio-isotopen komen in de natuur alleen sporen voor van de 223 Fr, dat onderdeel is van de vervalreeks van uranium-235 en een halfwaardetijd heeft van 22 minuten, en daarmee de langstlevende isotoop van francium is.
Overzicht
Nuclide
Z (p )
N (n )
Isotopische massa (u)
Halveringstijd
Radioactief verval
VP
Kernspin
Isotopische verhouding (molfractie )
Natuurlijk voorkomen (molfractie)
Excitatie-energie
199 Fr
87
112
199,00726(4)
16(7) ms
1/2+
200 Fr
87
113
200,00657(8)
24(10) ms
α
196 At
3+
200m Fr
60(110) keV
650(210) ms
α
196 At
10−
IT (zelden)
200 Fr
201 Fr
87
114
201,00386(8)
67(3) ms
α (99%)
197 At
(9/2− )
β+ (1%)
201 Rn
202 Fr
87
115
202,00337(5)
290(30) ms
α (97%)
198 At
(3+ )
β+ (3%)
202 Rn
202m Fr
330(90) keV
340(40) ms
α (97%)
198 At
(10− )
β+ (3%)
202 Rn
203 Fr
87
116
203,000925(17)
0,55(2) s
α (95%)
199 At
(9/2− )
β+ (5%)
203 Rn
204 Fr
87
117
204,000653(26)
1,7(3) s
α (96%)
200 At
(3+ )
β+ (4%)
204 Rn
204m1 Fr
50(4) keV
2,6(3) s
α (90%)
200 At
(7+ )
β+ (10%)
204 Rn
204m2 Fr
326(4) keV
1,7(6) s
(10− )
205 Fr
87
118
204,998594(8)
3,80(3) s
α (99%)
201 At
(9/2− )
β+ (1%)
205 Rn
206 Fr
87
119
205,99867(3)
± 16 s
β+ (58%)
206 Rn
(2+ , 3+ )
α (42%)
202 At
206m1 Fr
190(40) keV
15,9(1) s
(7+ )
206m2 Fr
730(40) keV
700(100) ms
(10− )
207 Fr
87
120
206,99695(5)
14,8(1) s
α (95%)
203 At
9/2−
β+ (5%)
207 Rn
208 Fr
87
121
207,99714(5)
59,1(3) s
α (90%)
204 At
7+
β+ (10%)
208 Rn
209 Fr
87
122
208,995954(16)
50,0(3) s
α (89%)
205 At
9/2−
β+ (11%)
209 Rn
210 Fr
87
123
209,996408(24)
3,18(6) min
α (60%)
206 At
6+
β+ (40%)
210 Rn
211 Fr
87
124
210,995537(23)
3,10(2) min
α (80%)
207 At
9/2−
β+ (20%)
211 Rn
212 Fr
87
125
211,996202(28)
20,0(6) min
β+ (57%)
212 Rn
5+
α (43%)
208 At
213 Fr
87
126
212,996189(8)
34,6(3) s
α (99,45%)
209 At
9/2−
β+ (0,55%)
213 Rn
214 Fr
87
127
213,998971(9)
5,0(2) ms
α
210 At
(1− )
214m1 Fr
123(6) keV
3,35(5) ms
α
210 At
(8− )
214m2 Fr
638(6) keV
103(4) ns
(11+ )
214m3 Fr
6477 keV
108(7) ns
(33+ )
215 Fr
87
128
215,000341(8)
86(5) ns
α
211 At
9/2−
216 Fr
87
129
216,003198(15)
0,70(2) µs
α
212 At
(1− )
β+ (2 × 10−7 %)
216 Rn
217 Fr
87
130
217,004632(7)
16,8(19) µs
α
213 At
9/2−
218 Fr
87
131
218,007578(5)
1,0(6) ms
α
214 At
1−
218m1 Fr
86(4) keV
22,0(5) ms
α
214 At
IT (zelden)
218 Fr
218m2 Fr
200(150) keV
219 Fr
87
132
219,009252(8)
20(2) ms
α
215 At
9/2−
220 Fr
87
133
220,012327(4)
27,4(3) s
α (99,65%)
216 At
1+
β− (0,35%)
220 Ra
221 Fr
87
134
221,014255(5)
4,9(2) min
α (99,9%)
217 At
5/2−
β− (0,1%)
221 Ra
CV (8,79 × −11 %)
207 Tl, 14 C
222 Fr
87
135
222,017552(23)
14,2(3) min
β−
222 Ra
2−
223 Fr
87
136
223,0197359(26)
22,00(7) min
β− (99,99%)
223 Ra
3/2−
sporen
α (0,006%)
219 At
224 Fr
87
137
224,02325(5)
3,33(10) min
β−
224 Ra
1−
225 Fr
87
138
225,02557(3)
4,0(2) min
β−
225 Ra
3/2−
226 Fr
87
139
226,02939(11)
49(1) s
β−
226 Ra
1−
227 Fr
87
140
227,03184(11)
2,47(3) min
β−
227 Ra
1/2+
228 Fr
87
141
228,03573(22)
38(1) s
β−
228 Ra
2−
229 Fr
87
142
229,03845(4)
50,2(4) s
β−
229 Ra
(1/2+ )
230 Fr
87
143
230,04251(48)
19,1(5) s
β−
230 Ra
231 Fr
87
144
231,04544(50)
17,6(6) s
β−
231 Ra
(1/2+ )
232 Fr
87
145
232,04977(69)
5(1) s
β−
232 Ra
Overzicht van isotopen per element
Zie ook
Bronnen, noten en/of referenties
(en ) R.B. Firestone, S.Y. Frank Chu & C.M. Baglin (1999) - Table of Isotopes (online versie van de cd-rom)
(en ) G. Audi, A.H. Wapstra, C. Thibault, J. Blachot & O. Bersillon (2003) - The NUBASE evaluation of nuclear and decay properties , Nuclear Physics A , 729 , pp. 3-128
(en ) J.R. de Laeter, J.K. Böhlke, P. De Bièvre, H. Hidaka, H.S. Peiser, K.J.R. Rosman & P.D.P. Taylor (2003) - Atomic weights of the elements. Review 2000 (IUPAC Technical Report) , Pure and Applied Chemistry , 75 (6), pp. 683–800
(en ) M.E. Wieser (2006) - Atomic weights of the elements 2005 (IUPAC Technical Report) , Pure and Applied Chemistry , 78 (11), pp. 2051–2066
(en ) David R. Lide (2004) - CRC Handbook of Chemistry and Physics (85th ed.), hoofdstuk 11, CRC Press - ISBN 978-0849304859