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Dimitri Ivanovitch Mendeleïev or Mendeleev (ДмитрийИвановичМенделеев), born the February 8th 1834 with Tobolsk and dead the February 2nd 1907 with Saint-Pétersbourg, is a Russian Chimiste .

He is mainly known for his work on the classification periodic of the elements, published in 1869 and also called table of Mendeleïev . He declared that the chemical elements could be arranged according to a model which made it possible to envisage the properties of the elements not yet discovered.

Childhood, studies and beginning of the scientific career

Mendeleïev was born with Tobolsk, in Siberia. He was the junior by the many children by Maria Dmitrievna Korniliev and Ivan Pavlovitch Mendeleïev (the thirteenth one according to Michael Gordin, a historian of sciences). At the fourteen years age, after the death of his/her father, Mendeleïev enters to the college of Tobolsk. In 1849, the family become poor settles with Saint-Pétersbourg, Dimitri between at the university in 1850. After having received its diploma, it contracted the Tuberculose what obliged it to move in the peninsula criméenne close to the Black Sea in 1855, where it became responsible for sciences of the local college. It returned completely cured to Saint-Pétersbourg in 1856. He studied chemistry with Saint-Pétersbourg where he was graduate in 1856. At 25 years, it came to work with Heidelberg with scientists like Robert Bunsen and Gustav Kirchhoff. In 1867, it was named professor of inorganic Chemistry with the Université of Saint-Pétersbourg.

Between 1859 and 1861 he worked on the density of gases in Paris, and the operation of the spectroscope with Gustav Kirchhoff in Heidelberg. In 1863, after its return in Russia, he became chemistry teacher at the technological institute and the university of Saint-Pétersbourg. The same year he married Feozva Nikitichna Leshcheva (ФеозваНикитичнаЛещева); this marriage showed a divorce. He married then Anna Ivanovna Popova (АннаИвановнаПопова).

Periodic classification

In 1866, Newlands enacted its law of the bytes. Mendeleïev had worked on a similar idea, and on March 6th, 1869, a formal presentation was made at the Russian company of chemistry, entitled the dependence between the properties of the atomic masses of the elements , stating:

the elements, when they are laid out according to their atomic mass, show an apparent periodicity their properties.
the elements which are similar with regard to their chemical properties have atomic weights which are more or less of the same value (for example Pt, Ir, Os) or which increases regularly (for example K, Rb, Cs).
the arrangement of the elements, or the groups of elements in the order of their atomic weights, corresponds to their alleged valence S, as well as, to a certain extent, with their distinctive chemical properties.
the elements which are most largely represented have small atomic weights.
the importance of the atomic weight determines the character of the element, just as the importance of the molecule the character of a made up body determines.
We must expect discovered many elements up to now unknown. For example of the elements similar to the Aluminum and the Silicium whose atomic mass would lie between 65 and 75.
the atomic mass of an element can sometimes be modified by a knowledge of the mass of its contiguous elements. Thus, the atomic weight of the Tellure must be between 123 and 126, and.
Certaines index properties of the elements cannot be 128 can be envisaged starting from their atomic mass.

Unknown of Mendeleïev, Lothar Meyer worked with a practically identical periodic classification although it never came to the idea from Meyer the possibility of envisaging the existence of new elements and to correct the atomic masses. Meyer and Mendeleïev can be regarded as the creators of this classification.

Other work

In addition to its work on the classification of the elements, Mendeleïev carried out very varied scientific research. The chemist and Russian historian of sciences L.A. Tchugayev defined it as a genious chemist, physicist of first class, prolix researcher in the field of the hydrodynamics, meteorology, geology, certain branches of the chemistry (explosive, oil, fuels…) and other disciplines close to chemistry and physics, an expert of chemical industry and chemistry in general, and an original thinker in the economic domain . In 1869, it was among the founders of the Russian Company of chemistry. He also worked on the theory and the effects of protectionism in agriculture.

In 1902, in an attempt to give a chemical explanation to the ether, he formulated a false assumption by supposing the existence of two inert chemical elements lighter than the Hydrogène. Lightest of both was supposed all to penetrate, and the heaviest one new element whose existence was supposed at the time and called coronium .

Mendeleïev also devoted much time and carried out important work for the determination of the nature of the solutions. In the field of the physical Chemistry, it worked on the thermal expansion of the liquids. It obtained in particular a formula similar to the Loi of Gay-Lussac of expansion of gases. In 1861, it anticipated the idea of Thomas Andrews of Température criticizes by defining the absolute boiling point of a compound like the temperature to which the cohesion of the liquid and the heat of vaporization become null and the liquid changes into vapor independently of the pressure and volume.

He also studied the origins of the Pétrole and concludes that the Hydrocarbure S are formed in the depths of the ground: " The capital fact to note is that oil was born in the depths from the ground, and it is there only that we must seek his origine".

National and international recognition

Although Mendeleïev was largely honoured by scientific organizations through Europe, its political activities worried the Russian government, which led to its resignation of the university of Saint-Pétersbourg on August 17th, 1890.

In 1893, it was named director of the office of the weights and measurements. Mendeleïev is also responsible for the scientific justification of the “optimal” proportion of 40 % of alcohol in Russian vodka.

In 1882, it received the Davy Medal of the Royal Society, in 1889 the Faraday Lectureship of the Royal society off chemistry and in 1905 the Medal Copley of the Royal Society. He died in Saint-Pétersburg and is buried with the Cimetière Volkovo, always in Saint-Pétersbourg. Element 101 was baptized Mendélévium in its honor.

Quotations

This material is too invaluable to be flaring; when we burn Pétrole, we burn money; it should be used as raw material of the chemical synthesis. (1882, in a letter addressed to the tsar Alexandre III)

Sources

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