Dmitri Mendeleev

Dmitri Ivanovich Mendeleyev ({{lang-ru|???????? ????????? ??????????}} {{Audio|ru-Dmitri_Mendeleev.ogg|listen}}) ({{OldStyleDate|8 February|1834|27 January}} in Tobolsk – {{OldStyleDate|2 February|1907|20 January}} 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 several cases he even ventured to question the accuracy of the accepted atomic weights, arguing that they did not correspond to those predicted by the Periodic Law, and here too subsequent research proved him 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 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.

Related Topics:
1902 - Element - Hydrogen - Aether

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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.

Related Topics:
Solution - Liquid - Dalton

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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 T. Andrews's 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.

Related Topics:
Physical chemistry - Gay-Lussac - 1861

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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.

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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.

Related Topics:
Alcohol - Vodka - Density

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

Related Topics:
Metric system - Russian Empire

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

Related Topics:
Smokeless powder - Nitrocellulose - 1892

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