An Overview about the Chemical Element Francium


Symbol: Fr

Atomic Number: 87

Atomic Mass: 223.0 amu (atomic mass units)

Melting Point: 27.0 C (300.15 K, 80.6 F)

Boiling Point: Unknown

Number of Protons: 87

Number of Electrons: 87

Number of Neutrons: 136

Classification: Metal

Group Name: Alkali Metal

Crystal Structure: Cubic

Density @ 293 K: Unknown

Color: Unknown

In 1939, the French chemist, Marguerite Catherine Perey was examining the decay chain of the radioactive rare earth element actinium. In doing so she found a new element, the radioactive alkali metal Francium. The element was named after Marguerite Catherine Perey’s home country of France.

Francium is considered to be a naturally occurring element but there is very little of this element to be found. It has been estimated that less than an ounce of francium exists in the total of the earths crust at any one time. For this reason scientists who wish to study the element must be able to produce it in the laboratory. There are two methods that have been employed for the artificial production of francium. It can be made by bombarding the element thorium with protons or the element radium with neutrons.

Even when it has been produced francium does not remain around for very long. The elements’ most stable isotope, francium-223, has a half-life of only 22 minutes. It decays by either beta decay to form radium-223 or alpha decay to form astatine -219. Other isotopes of francium are known. They have mass numbers ranging from 199 to 232. The isotope francium-215 has the shortest half-life at 86 nanoseconds.

With only a small amount of the element available and it having a short half-life very little as been discovered about its chemical interactions or its bulk properties. Francium has the Ionization Energy of 3.9 eV and an Oxidation State of +1. It is in Period Number 7 and Group Number 1 of the periodic table.

Some of the element’s chemistry and properties can be deduced from what is known of the other alkali metals. If francium was to be produced in any quantity it would be an extremely soft, ductile, metal and silver or white in color. Francium would probably react extremely violently with water. It may well react with ice at quite low temperatures and with the water vapor present in the air.

It is very unlikely that francium will ever have any industrial uses. Any quantity of the element that is produced is likely to be used for scientific research purposes only.