Background

Ethnicity: Ladenburg was a member of the well-known Jewish Ladenburg family.

Albert Ladenburg was born on July 2, 1842, in Mannheim, Germany. He was one of eight children of Leopold Ladenburg, a prosperous attorney, and his wife Delphine Picard.

Education

Ladenburg's father objected to the classical education given at Gymnasium and sent him to a school where little Latin and no Greek were taught. At the Polytechnicium in Karlsruhe he emphasized study of mathematics and languages, attempting to fill in the gaps of his earlier education. In 1860 Ladenburg went to Heidelberg and, inspired by Bunsen’s and Kirchhoff’s lectures, decided on chemistry, taking the Ph.D., summa cum laude, in the spring of 1863. He stayed on for two years, working with Ludwig Carius, beginning a lifelong friendship with Erlenmeyer, and shifting his interest from inorganic to organic chemistry.

Career

Ladenburg worked under Kekulé at Ghent in 1865; but despite the scientific excitement he found life at Ghent dull, and after a visit with Frankland in London, he began working with Wurtz in Paris.

Late in 1866 Friedel invited Ladenburg to work with him at the Ecole des Mines, where they began research on the compounds of silicon. Their concern centered on whether the new theories being developed about carbon compounds were applicable to the so-called inorganic elements and their compounds. Preliminary to synthesizing compounds containing two silicon atoms bonded to each other, they prepared dimethyldiethylmethane, the first known quarternary hydrocarbon, demonstrating that carbon can bond to four other carbon atoms as silicon was shown to do by Friedel and Crafts in their compound Si(C2H5)4. They also prepared silicon analogues of carboxylic acids, ethers, ketones, and alcohols. Believing that compounds of the lower oxidation states of metals contained two atoms of the metal per molecule, Ladenburg began the study of tin compounds. He prepared various organotin compounds, including triethylphenyl tin, but soon realized that such compounds could not resolve the question.

Ladenburg qualified as a teacher in January 1868, set up a laboratory in Heidelberg, and taught a course on the history of chemistry, publishing the revised lectures in 1869. That same year he criticized Kekule’s formula for benzene and suggested alternatives, including his prism formula. Ladenburg argued that in Kekule’s formula the 1,2-position is different from the 1,6-position and the 1,3-position may be different from the 1,5-position, whereas experimental evidence supported the identity of these positions. He moved to the University of Kiel in 1872 and, continuing his benzene researches, showed only three disubstitution products of benzene are possible, only one pentachlorobenzene exists, and mesitylene is symmetrical trimethylbenzene. In amassing evidence for the equivalence of the six benzene carbon atoms, Ladenburg recognized that he was weakening support for his prism formula and said in 1875 that there was no symbolic representation of benzene satisfying all requirements. In 1876, he summarized his views on benzene structure in Die Theorie der aromatischen Verbindungen, drawing attention to Korner’s method for ascertaining the structure of benzene derivatives.

In 1876, he began the study of alkaloids, concentrating on atropine and its derivatives. In 1884 Ladenburg began the work that resulted in the first synthesis of an alkaloid, coniine. He was the first to show that d, l-bases can be resolved by Pasteur’s method for resolving d, 1-acids. The acid tartrate was prepared and resolved, the coniine liberated, and the dextrorotatory form identified with naturally occurring coniine.

In 1889 Ladenburg became professor at Breslau (now Wroclaw), where he continued work on alkaloids and racemic compounds. He ascertained the formula of ozone as 03 and accurately determined the atomic weight of iodine in seeking an answer to the question of its position relative to tellurium in the periodic table.

Achievements

• Albert Ladenburg went down in history as a noted chemist. He is best remembered for his work with August Kekulé on structural theory and the structure of benzene. He is also remembered for his work with Charles-Adolphe Wurtz and Charles Friedel on organosilicon compounds and tin compounds.
  
  He was the recipient of the Davy Medal of the Royal Society in 1907.

Works

More photos

• book

  • Handwörterbuch der Chemie 1882
  • Uber den Einfluss der Naturwissenschaften auf die Weltanschauung 1903
  • Vortrage uber die Entwicklungsgeschichte der Chemie von Lavoisier bis zur 1907
  • Histoire du Developement de la Chimie Depuis Lavoisier Jusqu'a Nos Jours 1909
  • Entwickelung der chemie in den letzten zwanzig jahren 190
  • Naturwissenschaftliche Vorträge in gemeinverständlicher Darstellung 1911

Membership

Ladenburg was a member of the Berlin and Paris academies of sciences. He was also an honorary and foreign member of the Chemical Society of London.

• 

  Member

  Royal Prussian Academy of Sciences , Germany

• 

  Member

  French Academy of Sciences , France

• 

  Honorary member, foreign member

  Chemical Society of London , United Kingdom

Connections

Ladenburg married Margarete Pringsheim, the daughter of a professor of botany at Berlin, on September 19, 1876.

Father:

Leopold Ladenburg

Mother:

Delphine Picard

Spouse:

Margarete Pringsheim

Brother:

Heinrich Ladenburg

Sister:

Luise Ladenburg

Son:

Erich Robert Ladenburg

Son:

Rudolf Ladenburg

Son:

Edgar Ladenburg

teacher:

Robert Bunsen

teacher:

Gustav Kirchhoff

colleague:

Ludwig Carius

Friend:

Emil Erlenmeyer

colleague:

August Kekulé

References

• Dictionary of Scientific Biography, Volume 7
  1973