Johann W. Dobereiner

(13 December 1780 – 24 March 1849)

Johann Wolfgang Döbereiner

Introduction:

He is a German chemist. He is also a professor of chemistry and pharmacy at the University of Jena. He is best known for foreshadowing the periodic law for the chemical elements. He invented the first lighter, which was known as the Döbereiner's lamp.

University of Jena

The University of Jena, officially the Friedrich Schiller University Jena is a public research university located in Jena, Thuringia, Germany

Döbereiner's Lamp

Also called a "tinderbox" ("Feuerzeug")

Background:

Family - As a coachman's son, Dobereiner had little opportunity for formal schooling.

Education -

Dobereiner was self-educated, although his mother supervised his early instruction.
In 1784, his mother apprenticed him to an apothecary named Lutz.
In 1810, he became a professor at the University of Jena and studied chemistry at Strasbourg.

Personal relationship - After three years’ service with Lutz, he returned to Hof and married Clara Knab.

Contributions to Chemistry:

In 1812, Dobereiner engaged in the conversion of starch into sugar by Kirchhoff’s process.
Dobereiner made spongy platinum by decomposing platinum salts in solution and by exposing them to direct heat.
Dobereiner invented Dobereiner's lamp which is a pneumatic gas lighter (Platinfeuerzeug). It consists of a hydrogenation device that brought hydrogen to impinge on the finely divided platinum. The oxidation then produced white heat.
Dobereiner examined the weights of the chemical elements which aided the development of Mendeleev’s Periodic Table.

The Features of Periodic Table by Johann W. Dobereiner :

Dobereiner found that the atomic mass of strontium atom, Sr was similar to the average mass of calcium atom, Ca and barium atom, Ba. These elements had the same chemical properties. A similar condition occurred with chlorine, Cl, bromine, Br and iodine, I.
Later, Dobereiner found that the densities for some of these triads followed a similar pattern and called it as "Dobereiner's triads".
In 1829, Dobereiner discovered that the first element of each group cannot fit into such triads. He further examined such triads by other qualities - especially specific gravity and affinity.
Dobereiner found that the specific gravity (as well as the atomic weight) of selenium is equal to the mean specific gravity of sulphur and tellurium.
The intensity of chemical affinity of the salt-forming elements in the triads is inversely proportional to the atomic weight but is directly proportional for alkali-forming elements.
His classification showed the relationship between the chemical properties of elements and atomic mass.

Dobereiner's Triad and example

Awards and Honors:

Cross of the White Falcon
- Dobereiner neglected further development of his work on triads because of his diversified teaching schedule.
- However, his merit was civilly rewarded when he was made privy councillor.

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