Francium is a chemical element in the Periodic Table marked with an atomic number of 87 and with the chemical symbol Fr. Francium belongs to group 1 elements in the Periodic Table, which are Alkali Metals. It is preceded by Radon and it is followed by Radium. This chemical element is extremely rare.


Francium shares several group trends with the rest of the Alkali Metals it terms of physical and chemical properties. However, because of its rarity and because of its extreme heat of decay it is practically impossible to obtain a viewable solid or liquid sample of Francium. It is presumed that it would be a reflective, shiny metal like the rest of the Alkali Metal elements. This chemical element is highly radioactive and like all Alkali Metals Francium has one valence electron. It forms unstable isotopes and various compounds with other chemical elements.



Since its most stable isotope, Francium-223, has an extremely short half-life of up to 22 minutes, this chemical element is quite hard to study and explore properly, unlike the rest of the group 1 Alkali Metal elements.


Physical Characteristics of Francium

Because it belongs to the group 1 elements in the Periodic Table it is presumed that Francium has the same physical characteristics as the rest of the Alkali Metals when it comes to its color and hardness. Francium’s absolute melting points and boiling points haven’t been estimated with certainty, but its melting point is presumed to be around 27C. Of all naturally occurring chemical elements Francium is the least stable one. It has a +1 oxidation state and it forms strong, basic oxides.


Chemical Properties of Francium


Atomic Number – 87

Group – 1

Period – 7

Block – s

Electronic Configuration – 7s1

Relative Atomic Mass – 223 (223 g/mol)

Molecular Weight – 223

Electronegativity – 0.7

Density (G CM-3) – 1.87 g/cm3 at room temperature

Melting Point – 300 K; 27 °C; 80 °F

Boiling Point – 950 K; 677 °C; 1250 °F

Atomic Radius – 270pm

Isotopes – 33

Electronic Shell – 2, 8, 18, 32, 18, 8, 1


Discovery of Francium

There were many inconclusive and incomplete discovery attempts when it comes to Francium. The earliest alleged discoveries were made as early as the 1870s. However, a French student at the Parisian Curie Institute fully recognized and discovered Francium. She conducted various tests on the element and its isotopes by purifying a sample of the Actinium-227 isotope. After her tests ruled out that the newly discovered element was not among the rest of the Alkali Metals, she proposed the names Actinum-K and Catium for it, but eventually renamed it to Francium after her home country. The name Francium was officially legalized in 1949 by the International Union of Pure and Applied Chemistry.


Recognized by: Marguerite Perey (1939)

Known and discovered by: Marguerite Perey (1939)

Named by: Marguerite Perey


Uses and role of Francium

Because of the extreme rarity and the fact that Francium is significantly unstable as an element, it does not have any commercial applications. However, it has found various applications in science as part of spectroscopy experiments and researches in the area of present-day chemistry focusing on subatomic particles and energy levels. In other words, this particular chemical element plays a key role only in scientific research.


Francium on Earth

Francium is so rare that it does not occur naturally on Earth. Its isotope Francium-223 is a result of the alpha decay of the isotope Actinum-227. It also leaves traces in Thorium and Uranium minerals. However, this Alkali Metal element can be artificially created as a synthetic product of a nuclear reaction. Nevertheless, the element has never been synthesized in such sufficient amounts that it could be weighed.



Regardless of the fact that this particular Alkali Metal element is so rare and so unstable, Francium has been used in several ground-breaking experiments. One of these experiments ruled out that this element could be used in diagnosing various types of cancer. However, it was recently discovered that this possibility would be quite impractical.