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Wittig, Georg

(Encyclopedia)Wittig, Georg, 1897–1987, German chemist, Ph.D. Univ. of Marburg, 1926. During his career, Wittig was a professor at the universities of Braunschweig, Freiburg, Tübingen, and Heidelberg. He shared ...

psychosis

(Encyclopedia)psychosis sīkōˈsĭs [key], in psychiatry, a broad category of mental disorder encompassing the most serious emotional disturbances, often rendering the individual incapable of staying in contact wi...

nitrogen cycle

(Encyclopedia)CE5 Nitrogen cycle nitrogen cycle, the continuous flow of nitrogen through the biosphere by the processes of nitrogen fixation, ammonification (decay), nitrification, and denitrification. Nitrogen...

MacMillan, David W.C.

(Encyclopedia)MacMillan, David W.C., 1968–, b. Bellshill, U.K. Scotish chemist, James S. McDonnell Distiguished University Professor in Chemistry and ...

heterotroph

(Encyclopedia)heterotroph hĕtˈərətrōfˌ [key], living organism that obtains its energy from carbohydrates and other organic material. All animals and most bacteria and fungi are heterotrophic. In contrast, aut...

Pregl, Fritz

(Encyclopedia)Pregl, Fritz frĭts prāˈgəl [key], 1869–1930, Austrian physiologist and chemist, M.D. Univ. of Graz, 1894. He taught at the universities of Innsbruck (1910–13) and Graz (from 1913). For his met...

Fresnel, Augustin Jean

(Encyclopedia)Fresnel, Augustin Jean ōgüstăNˈ zhäN frānĕlˈ [key] 1788–1827, French physicist and engineer. He is known for his research on light, especially on conditions governing interference phenomena ...

ammonium sulfate

(Encyclopedia)ammonium sulfate, chemical compound, (NH4)2SO4, a colorless-to-gray, rhombohedral crystalline substance that occurs in nature as the mineral mascagnite. It is soluble in water and insoluble in alcohol...

potassium carbonate

(Encyclopedia)potassium carbonate, chemical compound, K2CO3, white, crystalline, deliquescent substance that forms a strongly alkaline water solution. It is available commercially as a white, granular powder common...

tabun

(Encyclopedia)tabun täˈbən [key], liquid chemical compound used as a nerve gas. It boils at 240℃ with some decomposition. The liquid is colorless to brownish; its vapors have a fruity odor similar to that of b...