Mendeleev's Periodic Table > Fr - Francium

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.

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 (Francium) :

MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass 		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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 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
MASS abundancy
Halflife
Particle, Energy
Decay Product(s)
Isotopic Mass		 232
5 sec
B-,6.370 MeV
Ra-232
232.0