b. 9 December 1868 Breslau, Germany (now Wroclaw, Poland)
d. 29 January 1934 Basel, Switzerland
Haber's father was a manufacturer of dyestuffs, so he studied organic chemistry at Berlin and Heidelberg universities to equip him to enter his father's firm. But his interest turned to physical chemistry and remained there throughout his life. He became Assistant at the Technische Hochschule in Karlsruhe in 1894; his first work there was on pyrolysis and electrochemistry, and he published his Grundrisse der technischen Electrochemie in 1898. Haber became famous for thorough and illuminating theoretical studies in areas of growing practical importance. He rose through the academic ranks and was appointed a full professor in 1906. In 1912 he was also appointed Director of the Institute of Physical Chemistry and Electrochemistry at Dahlem, outside Berlin.
Early in the twentieth century Haber invented a process for the synthesis of ammonia. The English chemist and physicist Sir William Crookes (1832-1919) had warned of the danger of mass hunger because the deposits of Chilean nitrate were becoming exhausted and nitrogenous fertilizers would not suffice for the world's growing population. A solution lay in the use of the nitrogen in the air, and the efforts of chemists centred on ways of converting it to usable nitrate. Haber was aware of contemporary work on the fixation of nitrogen by the cyanamide and arc processes, but in 1904 he turned to the study of ammonia formation from its elements, nitrogen and hydrogen. During 1907-9 Haber found that the yield of ammonia reached an industrially viable level if the reaction took place under a pressure of 150-200 atmospheres and a temperature of 600°C (1,112°F) in the presence of a suitable catalyst-first osmium, later uranium. He devised an apparatus in which a mixture of the gases was pumped through a converter, in which the ammonia formed was withdrawn while the unchanged gases were recirculated. By 1913, Haber's collaborator, Carl Bosch had succeeded in raising this laboratory process to the industrial scale. It was the first successful high-pressure industrial chemical process, and solved the nitrogen problem. The outbreak of the First World War directed the work of the institute in Dahlem to military purposes, and Haber was placed in charge of chemical warfare. In this capacity, he developed poisonous gases as well as the means of defence against them, such as gas masks. The synthetic-ammonia process was diverted to produce nitric acid for explosives. The great benefits and achievement of the Haber-Bosch process were recognized by the award in 1919 of the Nobel Prize in Chemistry, but on account of Haber's association with chemical warfare, British, French and American scientists denounced the award; this only added to the sense of bitterness he already felt at his country's defeat in the war. He concentrated on the theoretical studies for which he was renowned, in particular on pyrolysis and autoxidation, and both the Karlsruhe and the Dahlem laboratories became international centres for discussion and research in physical chemistry.
With the Nazi takeover in 1933, Haber found that, as a Jew, he was relegated to second-class status. He did not see why he should appoint staff on account of their grandmothers instead of their ability, so he resigned his posts and went into exile. For some months he accepted hospitality in Cambridge, but he was on his way to a new post in what is now Israel when he died suddenly in Basel, Switzerland.