|
87
Fr
(223)
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This uranium ore sample contains about 100 000 atoms of francium-223 (3.3 x 10 -20 g).
Francium is radioactive; less than 30 g of it exists on Earth at any given time. Photo by Konrad Roeder
| Classification: | Francium is an alkali metal |
| Color: | silver-gray-metallic (presumed) |
| Atomic weight: | (223), no stable isotopes |
| State: | solid |
| Melting point: | 27 oC , 300 K |
| Boiling point: | 677 oC, 950 K |
| Shells: | 2,8,18,32,18,8,1 |
| Electron configuration: | [Rn] 7s1 |
| Density @ 20oC: | 1.873 g/cm3 |
| Atomic volume: | 71.07 cm3/mol |
| Structure: | believed to be bcc: body-centered cubic |
| Hardness: |
Discovery of Francium
Francium was discovered by Marguerite Perey in 1939 when examining the radioactive decay of actinium-227.
When actinium-227 emits an alpha-particle the resulting nucleus is francium-223.
Francium's discovery took place at the Curie Institute in Paris, and the element's takes its name from France.
The discovery completed humankind's discoveries of naturally occurring elements.
All elements discovered thereafter have been produced synthetically.
Appearance & Characteristics
Francium
Harmful effects:
Francium is highly radioactive.
Characteristics:
Francium is a heavy, unstable, radioactive metal with a maximum half-life of only 22 minutes. It has a low melting point (27 oC, 81 oF) and, if enough of it could be accumulated, it would be liquid in a warm room.
Francium is the second rarest element in the Earth's crust, next to astatine. Less than thirty grams of francium exists on Earth at any given time.
Francium is the least electronegative of all the elements, therefore it should be the most chemically reactive alkali metal. Unfortunately, it is not available in sufficient quantities to show it reacting with water - it is made in tiny quantities in particle accelerators. In theory, its reaction with water would be more violent than cesium's and very much more violent than sodium's.
Francium has been studied most recently at Stony Brook University, New York. Scientists there trapped up to ten thousand francium atoms at a time using laser beams in a magnetic field in order to measure their properties.
Commercially, there are no uses for francium, due to its rarity and instability. It is used for research purposes only.
Francium is highly radioactive.
Characteristics:
Francium is a heavy, unstable, radioactive metal with a maximum half-life of only 22 minutes. It has a low melting point (27 oC, 81 oF) and, if enough of it could be accumulated, it would be liquid in a warm room.
Francium is the second rarest element in the Earth's crust, next to astatine. Less than thirty grams of francium exists on Earth at any given time.
Francium is the least electronegative of all the elements, therefore it should be the most chemically reactive alkali metal. Unfortunately, it is not available in sufficient quantities to show it reacting with water - it is made in tiny quantities in particle accelerators. In theory, its reaction with water would be more violent than cesium's and very much more violent than sodium's.
Francium has been studied most recently at Stony Brook University, New York. Scientists there trapped up to ten thousand francium atoms at a time using laser beams in a magnetic field in order to measure their properties.
Uses of Francium
Commercially, there are no uses for francium, due to its rarity and instability. It is used for research purposes only.
Abundance & Isotopes
Abundance earth's crust: ~ 0 parts per million, ~ 0 parts per million
Abundance solar system: ~ 0 parts per billion by weight, ~ 0 parts per billion by moles
Cost, pure: $ per 100g
Cost, bulk: $ per 100g
Source:Francium occurs naturally as a result of the alpha radioactive decay of actinium.
Isotopes: Francium has 33 isotopes whose half-lives are known, with mass numbers 200 to 232. None are stable. 223Fr has the longest half-life at 21.8 minutes.
Abundance solar system: ~ 0 parts per billion by weight, ~ 0 parts per billion by moles
Cost, pure: $ per 100g
Cost, bulk: $ per 100g
Source:Francium occurs naturally as a result of the alpha radioactive decay of actinium.
Isotopes: Francium has 33 isotopes whose half-lives are known, with mass numbers 200 to 232. None are stable. 223Fr has the longest half-life at 21.8 minutes.
Energies
Specific heat capacity: J g-1 K-1
Heat of fusion: 2 kJ mol-1
1st ionization energy: 384 kJ mol-1
3rd ionization energy: kJ mol-1
Heat of fusion: 2 kJ mol-1
1st ionization energy: 384 kJ mol-1
3rd ionization energy: kJ mol-1
Heat of atomization: 73 kJ mol-1
Heat of vaporization : 64 kJ mol-1
2nd ionization energy: kJ mol-1
Electron affinity: kJ mol-1
Heat of vaporization : 64 kJ mol-1
2nd ionization energy: kJ mol-1
Electron affinity: kJ mol-1
Oxidation & Electrons
Shells: 2,8,18,32,18,8,1
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 0.7
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 0.7
Electron configuration: [Rn] 7s1
Maximum oxidation number: 1
Max. common oxidation no.: 1
Polarizability volume: 48.7 Å3
Maximum oxidation number: 1
Max. common oxidation no.: 1
Polarizability volume: 48.7 Å3
Reactions & Compounds
Reaction with air:
Reaction with 15 M HNO3:
Oxide(s):
Hydride(s):
Reaction with 15 M HNO3:
Oxide(s):
Hydride(s):
Reaction with 6 M HCl: vigorous, ⇒ H2, FrCl
Reaction with 6 M NaOH: vigorous, ⇒ H2, FrOH
Chloride(s):
Reaction with 6 M NaOH: vigorous, ⇒ H2, FrOH
Chloride(s):
Radius
Atomic radius: pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): pm
Ionic radius (1+ ion): 194 pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Conductivity
Thermal conductivity: 3.61 W m-1 K-1
Electrical conductivity: x 10-6 S m-1
Cite this Page
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