Georges Friedel (19 July 1865 – 11 December 1933) was a French mineralogist and crystallographer.

Life

Georges was the son of the chemist

Charles Friedel Charles Friedel (; 12 March 1832 – 20 April 1899) was a French chemist and mineralogist. Life A native of Strasbourg, France, he was a student of Louis Pasteur at the Sorbonne. In 1876, he became a professor of chemistry and mineralogy at ...

. Georges' grandfather was Louis Georges Duvernoy who held the chair in comparative anatomy from 1850 to 1855 at the

Muséum national d'histoire naturelle The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is loc ...

. Georges studied at the École Polytechnique in Paris and the École Nationale des Mines in

St. Etienne ST, St, or St. may refer to: Arts and entertainment * Stanza, in poetry * Suicidal Tendencies, an American heavy metal/hardcore punk band * Star Trek, a science-fiction media franchise * Summa Theologica, a compendium of Catholic philosophy an ...

, and was a student of François Ernest Mallard. In 1893 he obtained a professorship at the École Nationale des Mines, the director of which he would later become. After the

First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

, he returned as a professor at the University of Strasbourg in

Alsace Alsace (, ; ; Low Alemannic German/ gsw-FR, Elsàss ; german: Elsass ; la, Alsatia) is a cultural region and a territorial collectivity in eastern France, on the west bank of the upper Rhine next to Germany and Switzerland. In 2020, it had ...

. Due to ill health, he took early retirement in 1930, and died in 1933. He was married with five children.

Scientific works

Like his teacher Mallard, Friedel concerned himself with the theories of Auguste Bravais, the founder of crystallography. Friedel was able to demonstrate the theoretical ideas of Bravais (the

Bravais lattice In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of discrete translation operations described in three dimensional space by : \mathbf = n_1 \mathbf_1 + n_2 \mathbf_2 + n ...

) with the help of x-ray diffraction experiments on

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

s, and so provide the physical basis therefore. One of his most important discoveries was the law that now bears his name.

Friedel's salt

In 1897, Georges Friedel synthesised and identified calcium chloroaluminate which received his name. Georges Friedel also synthesised

calcium aluminate Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

in 1903 in the framework of his work on the macles theory.

Mesomorphic states of matter

The presumption that solid and liquid are adjacent states of matter was undercut by

Friedrich Reinitzer Friedrich Richard Reinitzer (25 February 1857 in Prague – 16 February 1927 in Graz) was an Austrian botanist and chemist. In late 1880s, experimenting with cholesteryl benzoate, he discovered properties of liquid crystals (named later by Ot ...

in 1888 when he noted a cloudy mesophase of cholesteryl benzoate between 145.5 °C and 178.5 °C. The subject was taken up in Germany, and in 1907 also in France by Georges Friedel and

François Grandjean François () is a French masculine given name and surname, equivalent to the English name Francis. People with the given name * Francis I of France, King of France (), known as "the Father and Restorer of Letters" * Francis II of France, Kin ...

, as they described the "focal conic liquid". Friedel contributed his ''Mesomorphic States of Matter'' to the Annales des Physiques in 1922. This two-hundred-page work established much of the current terminology in mesophase physics. First, the '' nematic phase'' he characterized as having microscopic threads (these threads are today interpreted as disclinations in the director-field in the mesophase). Second, Friedel coined the term '' smectic phase'' for a layered mesophase having the structure of neat soap. Third, Friedel use the term '' cholesteric phase'' for materials like cholesteryl benzoate, and noted that such mesophases "involve strong twists around a direction normal to the positive

optical axis An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens, microscope or telescopic sight. The optical axis is an imaginary line that defines the path along which light pro ...

".David Dunmur and Tim Sluckin (2011) ''Soap, science, and flat-screen TVs: a history of liquid crystals''. pp. 80–90,

Oxford University Press Oxford University Press (OUP) is the university press of the University of Oxford. It is the largest university press in the world, and its printing history dates back to the 1480s. Having been officially granted the legal right to print book ...

Scientists have followed Friedel's classification and the term '' mesophase'' for the intermediate states has also been adopted from him. He was of the conviction that the term liquid crystal did not bear scrutiny. Indeed, :The liquid crystals were not crystals at all, but peculiar liquids with some hint of solid properties. In 1931 Georges published, with his son

Edmond Friedel Edmond is a given name related to Edmund. Persons named Edmond include: * Edmond Canaple (1797–1876), French politician * Edmond Chehade (born 1993), Lebanese footballer * Edmond Conn (1914–1998), American farmer, businessman, and politician ...

, the results of their X-ray crystallography studies: "The physical properties of the mesophases in general, and their importance in a scheme of classification."''Zeitschrift für Kristallographie'' 79:1–60.

Important publications

* 1904: ''Groupements cristallins'' * 1907: ''Etudes sur les lois de Bravais'' * 1922: ''Les états mésomorphes de la matiere''

References

External links

* François Grandjean (1935
George Friedel
''Bulletin de la Société Française de Minéralogie'', weblink from ''Annales des Mines'' (French). * Maurice Kleman (2005
Georges Friedel et "Les phases mésomorphes de la matière".
weblink to ''Institut de Minéralogie et de Physique des Milieux Condensés'' (French). {{DEFAULTSORT:Friedel, Georges 1865 births 1933 deaths Scientists from Mulhouse École Polytechnique alumni People from Alsace-Lorraine Crystallographers Liquid crystals French mineralogists