Fr - Francium

Rare, reactive and radioactive, francium is hard to come by - only about a tenth of a mole exists at any time. Possibly observed in 1931 by Fred Allison, who called it virginium, the element was discovered and confirmed in 1939 by Marguerite Perey, in decay products of actinium. Visit the State University of New York at Stony Brook's website where they make and experiment with francium.

Atomic number - 87 Density g/mL 1 .87
Atomic weight u 223 .0197 Melting point K 300 .2
Bonding radius A - Boiling point K 950
Atomic radius A - Heat of vaporization kJ/mol -
Ionization Potential V 4 .08 Heat of fusion kJ/mol -
Electronegativity - 0 .7 Specific heat J/gK -
The oxide is a strong base.
Crystal are body centered cubic.

Electron config. : [Rn] 7s1


Isotopes of Fr: Click mass number for decay process, product for element page.


201
48 msec
a/EC,7.540
At-197/Rn-201
201.00397
202
0.34 sec
a/EC,7.389
At-198/Rn-202
202.00332
203
0.55 sec
a/EC,7.280
At-199/Rn-203
203.00105
204
1.7 sec
a/EC,7.170
At-200/Rn-204
204.00064
205
3.85 sec
a/EC,7.060
At-201/Rn-205
204.99866
206
15.9 sec
a/EC,6.926
At-202/Rn-206
205.99848
207
14.8 sec
a/EC,6.900
At-203/Rn-207
206.99685
208
59.1 sec
a/EC,6.770
At-204/Rn-208
207.99713
209
50.0 sec
a/EC,6.777
At-205/Rn-209
208.99592
210
3.18 min
a/EC,6.700
At-206/Rn-210
209.99640
211
3.10 min
a/EC,6.660
At-207/Rn-211
210.99552
212
20.0 min
a/EC,5.117
At-208/Rn-212
211.99618
213
34.6 sec
a/EC,6.905
At-209/Rn-213
212.99617
214
5.0 msec
a,8.589 MeV
At-210
213.99895
215
86 nsec
a,9.540 MeV
At-211
215.00032
216
0.70 usec
a/EC,9.175
At-212/Rn-216
216.00318
216a
71 nsec
a,9.308 MeV
At-212
216.00333
217
16 usec
a,8.469 MeV
At-213
217.00461
218
1.0 msec
a,8.014 MeV
At-214
218.00756
219
20 msec
a,7.449 MeV
At-215
219.00924
220
27.4 sec
a/B-,6.801
At-216/Ra-220
220.01231
221
4.9 min
a/B-,6.458
At-217/Ra-221
221.01424
222
14.2 min
B-,2.033 MeV
Ra-222
222.01754
223
22.00 min
a/B-,1.149
At-219/Ra-223
223.01973
224
3.33 min
B-,2.830 MeV
Ra-224
224.02323
225
4.0 min
B-,1.866 MeV
Ra-225
225.02560
226
49 sec
B-,3.670 MeV
Ra-226
226.02933
227
2.47 min
B-,2.490 MeV
Ra-227
227.03184
228
39 sec
B-,4.300 MeV
Ra-228
228.03574
229
50.2 sec
B-,4.480 MeV
Ra-229
229.03881
230
19.1 sec
B-,2.560 MeV
Ra-230
230.04295
231
17.5 sec
B-,7.175 MeV
Ra-231
231.04618
232
5 sec
B-,6.370 MeV
Ra-232
232.0
MASS abund.
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass