Chemist, b. 8 February (27 January*) 1834 (Tobolsk, Russia), d. 2 February (20 January*) 1907 (St. Petersburg).
Mendeleyev's father, the director of the gymnasium of Tobolsk in Siberia, became blind in the year when Dmitry was born, the 17th and last child of the family. His mother then leased and operated a glass factory for 13 years. In 1847 her husband died and the factory burnt down. Faced with no prospects in Tobolsk, she took her remaining two dependent children to Moscow with the aim to get Dmitry into university.
Moscow University did not take students from Siberia then, and the same applied to the University of St. Petersburg and to the medical school in the same city. Eventually, less than one year before her death, Mendeleyev's mother managed to have her son accepted at the Pedagogic Institute, from which he qualified as a teacher in 1855 with a gold medal for outstanding achievements.
Because he was not of robust health Mendeleyev asked for and received a posting to the Crimea's main city Odessa, where he spent his leisure time on chemical studies. After one year he returned to St. Petersburg to obtain a degree in chemistry. In the following year 1857 he obtained a position at the university.
After two years the government sent Mendeleyev to the University of Heidelberg, where the chemist Robert Bunsen and the physicist Gustav Kirchhoff were teaching, to expand his studies. During his time in Heidelberg Mendeleyev attended the First International Chemical Congress of 1860 that had been called to standardize chemical nomenclature and to agree on a definition of equivalent weight, atomic weight, and molecular weight. Mendeleyev did not play a major role at the Congress, which was attended by 140 delegates, but a paper distributed by the Italian chemist Stanislao Cannizzaro on the difference between atomic weight and molecular weight left a great impression on him.
Mendeleyev returned to St. Petersburg in 1861 but did not find continuous employment until 1864, when he was appointed professor at the Technical Institute. In 1867 he became professor of general chemistry at the University.
Because he could not find a suitable textbook for his students, Mendeleyev wrote the Principles of Chemistry during 1868 - 1870. Trying to present chemistry in a didactical and organized way, he studied the relationship between the properties of elements as a basis for their classification. It was not the first such attempt - John Dalton, Johann Döbeeiner and William Odling had tried the same - but the most successful of all and resulted in the periodic table of elements or periodic law.
The basis of all classification attempts had been the idea of atomic weight. Mendeleyev realized that when all elements are arranged in order of increasing atomic weight a periodicity of properties is discovered, which enables the study of chemical reactions for groups of comparable elements rather than in isolation. To arrange the known elements in such a table of relationships required gaps, which Mendeleyev claimed would be filled through the discovery of new elements in due course. Based on the relationships underlying the table, Mendeleyev predicted the properties of several of the missing elements. Within 20 years three new elements with the predicted properties were discovered.
The Principles of Chemistry were translated into many languages and became a standard reference for chemical research. Its periodic table served as a guide in the study of natural transformation of elements through radioactivity.
Mendeleyev considered it the responsibility of scientists to act beyond the classroom and supported the progressive ideas of the time. In 1865 he established a farm to demonstrate the improvement of Russian agriculture through the application of scientific knowledge. While in Paris in 1867 in charge of the Russian pavilion at the Paris Exhibition he studied the French chemical industry and on his return improved the Russian soda industry. He took a close interest in the efficiency of oil production and criticized the presence of foreign interests in the Russian oil industry.
His support of progressive forces and criticism of current practices made Mendeleyev enemies, and in 1880 he was refused advancement from corresponding member of the Academy of Sciences to full membership. In 1890 he was dismissed from his position at the university for supporting a student petition against unjust treatment.
Mendeleyev continued to be held in highest regard by scientists around the world, and the Russian government could not afford to send him into internal isolation. After less than a year he was given the official task of setting up a new system of import duties for heavy chemicals, and in 1893 he was appointed director of the Bureau of Weights and Measures, but he never again held an academic position. International science honoured him by inviting him to give the annual Faraday Lecture for 1889 in London.
* Date in the Russian calendar of the time.
Greenaway, F. (1995) Dmitry Ivanovich Mendeleyev . Encyclopaedia Britannica 15th ed.
Photo: public domain (Wikipedia)