Per Theodor Cleve
Per Theodor Cleve was a nineteenth-century expert in agricultural chemistry, inorganic and organic chemistries, geology, mineralogy, and oceanography.
Cleve's early schooling was in Stockholm, and after passing final examinations he went to Uppsala, Sweden, to study mineralogy and other sciences. Cleve earned a master's degree (M.Sc.) at the age of twenty-two years and completed his doctorate (Ph.D.) just one year later. During these years he received several travel grants that enabled him to visit laboratories in France, England, Italy, and Switzerland.
Some milestones of Cleve's teaching career at Uppsala University are: In 1860 the twenty-year-old student was appointed assistant professor in mineralogy; in 1863, at the age of twenty-three, he was named assistant professor in organic chemistry; and a year later he became professor of general chemistry and agricultural chemistry.
In Paris Cleve visited the research laboratory of chemist Charles Adolphe Wurtz (1817–1884). The laboratory was unique in Europe in its attraction of young chemists, and here Cleve made many friends. Wurtz drew Cleve's attention to complex metal compounds. At age twenty-one Cleve published his first research paper on a complex chromium compound he had prepared and analyzed. In this paper he demonstrated that the compound was chromium trichloride-ammonia-water (in a 1:4:1 ratio). He later turned to the study of complex platinum compounds, of which he prepared hundreds. In 1872 Cleve, now thirty-two years old, published the results of this study in the Transactions of the Royal Swedish Academy of Sciences.
Cleve studied the group of elements known as the lanthanide elements. In 1879 he discovered two new lanthanide elements: holmium and thulium. The following year he undertook a thorough investigation of the newly discovered element scandium and proved that it had the properties predicted by Dimitri Mendeleev years earlier with his discovery of the periodic law and his publication of The Periodic Table.
Cleve's most celebrated work in organic chemistry was the preparation and characterization of the isomeric aminonaphthalenesulfonic acids, today called Cleve's acids.
In 1894 Cleve was awarded the Davy Medal by the Royal Society in London.
Brock, William (1993). The Norton History of Chemistry. New York: Wiley.
Greenberg, Arthur (2000). A Chemical History Tour. New York: Wiley.