(1780–1849) German chemist
Born the son of a coachman in Hof an der Saale, Germany, Döbereiner had little formal education and had worked as an assistant to apothecaries in several places from the age of 14. He was largely self-taught in chemistry and was encouraged by Leopold Gmelin whom he met at Strasbourg. After several failures in business, he was appointed assistant professor of chemistry at Jena (1810).
In 1823 he discovered that hydrogen would ignite spontaneously in air over platinum sponge, and subsequently developed the Döbereiner lamp to exploit this phenomenon. Döbereiner was interested in catalysis in general and discovered the catalytic action of manganese dioxide in the decomposition of potassium chlorate. His law of triads (1829), based on his observation of regular increments of atomic weight in elements with similar properties, was an important step on the way to Dmitri Mendeleev's periodic table. Thus in triads such as calcium, strontium, and barium or chlorine, bromine, and iodine, the middle element has an atomic weight that is approximately the average of the other two. It is also intermediate in chemical properties between the other two elements. Döbereiner also worked in organic chemistry.
Subjects: Science and Mathematics.