Dmitri Mendeleev

Portrait of Dmitri Mendeleyev by Ilya Repin

Dmitriy Ivanovich Mendeleyev (Russian: Дми́трий Ива́нович Менделе́ев ) (8 February [O.S. 27 January] 1834 in Tobolsk – 2 February [O.S. 20 January] 1907 in Saint Petersburg), was a Russian chemist. He is renowned for being one of the two scientists who created the first version of the periodic table of elements. Unlike other contributors to the table, Mendeleyev managed to predict the properties of elements yet to be discovered. In some cases he even correctly questioned the accuracy of accepted atomic weights, arguing that they did not correspond to those predicted by the Periodic Law.

Biography

Mendeleyev was born in Tobolsk, Siberia, 13th of 17 children of Ivan Pavlovich Mendeleyev and Maria Dmitrievna Mendeleyeva (nee Kornilieva). At the age of fourteen, after the death of his father, Mendeleyev attended the Gymnasium in Tobolsk.

In 1849, the now poor family Mendeleyev relocated to St. Petersburg, where he entered the Main Pedagogical Institute in 1850. After graduating, an illness that was diagnosed as tuberculosis caused him to move to the Crimean Peninsula on the northern coast of the Black Sea in 1855, where he became chief science master of the local gymnasium. He returned with fully restored health to St. Petersburg in 1856.

Between 1859 and 1861 he worked on the capillarity of liquids and the workings of the spectroscope in Heidelberg. In 1862, he married Feozva Nikitichna Leshcheva; the marriage ended in divorce, though not before he had married Anna Ivanovna Popova; their daughter Lyubov eventually became the wife of the famous Russian poet Alexander Blok. In 1864, after returning to Russia, he became Professor of Chemistry at the Technological Institute and the University of St. Petersburg.

Though Mendeleyev was widely honored by scientific organizations all over Europe, including the Copley Medal from the Royal Society of London he resigned from St. Petersburg University on August 17, 1890. In 1893, he was appointed Director of the Bureau of Weights and Measures. Mendeleyev also investigated the composition of oil fields, and helped to found the first oil refinery in Russia.

Mendeleyev died in 1907 in St. Petersburg, Russia from influenza. Element number 101, the radioactive mendelevium, is named after him.

Periodic table

File:Dmendeleev.jpg

On March 6, 1869, Mendeleyev made a formal presentation to the Russian Chemical Society, entitled The Dependence Between the Properties of the Atomic Weights of the Elements, which described elements according to both weight and valence. This presentation stated that

1. The elements, if arranged according to their atomic weights, exhibit an apparent periodicity of properties.
2. Elements which are similar as regards to their chemical properties have atomic weights which are either of nearly the same value (e.g., Pt, Ir, Os) or which increase regularly (e.g., K, Rb, Cs).
3. The arrangement of the elements or of groups of elements in the order of their atomic weights, corresponds to their so-called valencies, as well as, to some extent, to their distinctive chemical properties; as is apparent among other series in that of Li, Be, B, C, N, O, and F.
4. The elements which are the most widely diffused have small atomic weights.
5. The magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body.
6. We must expect the discovery of many as yet unknown elements–for example, two elements, analogous to aluminum and silicon, whose atomic weights would be between 65 and 75.
7. The atomic weight of an element may sometimes be amended by a knowledge of those of its contiguous elements. Thus the atomic weight of tellurium must lie between 123 and 126, and cannot be 128.
8. Certain characteristic properties of elements can be foretold from their atomic weights.

Unknown to Mendeleyev, two others had also been working on their own tables of elements. One was John Newlands, who published his Law of Octaves in 1864. However, the lack of spaces for undiscovered elements and the placing of two elements in one box were criticised and his ideas were not accepted.

Another was Lothar Meyer, who published work in 1864, describing 28 elements, classified not by atomic weight but by valence alone. Like Newlands, Meyer did not seem to come to the idea of predicting new elements and correcting atomic weights.

Only a few months after Mendeleyev published his periodic table of all known elements (and predicted several new elements to complete the table, plus some corrected atomic weights), Meyer published a virtually identical table. Some people consider Meyer and Mendeleyev the cocreators of the periodic table, although most agree that Mendeleyev's accurate prediction of the qualities of what he called eka-silicon (germanium), eka-aluminum (gallium), and eka-boron (scandium) lands him the lion's share of credit. In any case, at the time Mendeleyev's predictions greatly impressed his contemporaries and most of them were eventually found to be correct.

Other achievements

In 1902, in an attempt at a chemical conception of the ether, he put forward the (wrong) hypothesis that there are in existence two chemical elements of smaller atomic weight than hydrogen, and that the lighter of these is a chemically inert, exceedingly mobile, all-penetrating and all-pervading gas, which constitutes the aether.

Mendeleyev also devoted much study to the nature of such indefinite compounds as solutions, which he looked upon as homogeneous liquid systems of unstable dissociating compounds of the solvent with the substance dissolved, holding the opinion that they are merely an instance of ordinary definite or atomic compounds, subject to Dalton's laws.

In another department of physical chemistry he investigated the expansion of liquids with heat, and devised a formula for its expression similar to Gay-Lussac's law of the uniformity of the expansion of gases, while so far back as 1861 he anticipated Thomas Andrews' conception of the critical temperature of gases by defining the absolute boiling-point of a substance as the temperature at which cohesion and heat of vaporization become equal to zero and the liquid changes to vapour, irrespective of the pressure and volume.

Mendeleyev wrote largely on chemical topics, his most widely known book probably being The Principles of Chemistry, which was written in 1868-1870, and has gone through many subsequent editions in various languages.

Mendeleyev is often credited for the scientific justification of the "optimal" ratio of alcohol of 40% (80 proof) used in vodka. The source for the attribution was his doctorate thesis "On Composing Alcohol with Water". The thesis dealt primarily with the physical properties of water-alcohol solutions, such as density.

He is given credit for the introduction of the metric system to the Russian Empire.

He had invented pyrocollodion, a kind of smokeless powder based on nitrocellulose, and in 1892 organised its manufacture.

See also

• Mendeleev's predicted elements
• Abiogenic petroleum origin

Further reading

• Michael Gordin, A Well-Ordered Thing: Dmitrii Mendeleev and the Shadow of the Periodic Table, Basic Books, 2004, ISBN 046502775X

External links

Biographies

• Biography by Roger Rumppe and Michael E. Sixtus, care of the Woodrow Wilson Leadership Program in Chemistry. 20 sources. Notes, among other things, that various sources list D.M.'s siblings as being 10 to 16 in number.

Periodic Table

• Original Periodic Table, annotated
• Mendeleyev's first draft version of the Periodic Table, 17 February 1869

Other

• References about Mendeleyev, maintained by Eugene V. Babaev, last updated May 2005 (as of December 2005).
• Faraday Lecture by Mendeleyev, July 4, 1889, annotated
• Mendeleyev and Sanskrit
• Picture of Mendeleyev, Edgar Fahs Smith Collection, University of Pennsylvania