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vermilion

(Encyclopedia)vermilion, vivid red pigment of durable quality. It is a chemical compound of mercury and sulfur and is known as red sulfide of mercury; it was formerly obtained by grinding pure cinnabar but is now c...

mixture

(Encyclopedia)mixture, in chemistry, a physical combination of two or more pure substances (i.e., elements or compounds). A mixture is distinguished from a compound, which is formed by the chemical combination of t...

Gnathustomulida

(Encyclopedia)Gnathustomulida nāˌthyəstəmyo͞oˈlĭdə [key], phylum of microscopic worms described in 1956 that have elongated bodies, cilia, and are hermaphroditic. The 80 known species in this group are geog...

iridescence

(Encyclopedia)iridescence ĭrˌədĕsˈəns [key], exhibition of rainbowlike colors on a surface. It usually results from interference when light composed of different wavelengths is reflected from the superficial ...

coal tar

(Encyclopedia)coal tar, product of the destructive distillation of bituminous coal. Coal tar can be distilled into many fractions to yield a number of useful organic products, including benzene, toluene, xylene, na...

Baumeister, Willi

(Encyclopedia)Baumeister, Willi vĭlˈē bouˈmīstər [key], 1889–1955, German artist. Influenced by primitive art and Miro's surrealism, Baumeister created abstractions that contain mechanical and organic forms...

Butlerov, Aleksandr Mikhailovich

(Encyclopedia)Butlerov, Aleksandr Mikhailovich əlyĭksänˈdər mēkhīlˈəvĭch bo͞otˈlyərôf [key], 1825–86, Russian chemist. As professor at the Univ. of Kazan he founded the first school of Russian chemi...

lactic acid

(Encyclopedia)lactic acid, CH3CHOHCO2H, a colorless liquid organic acid. It is miscible with water or ethanol. Lactic acid is a fermentation product of lactose (milk sugar); it is present in sour milk, koumiss, leb...

acetylcholine

(Encyclopedia)acetylcholine əsētˌəlkōˈlēn [key], a small organic molecule liberated at nerve endings as a neurotransmitter. It is particularly important in the stimulation of muscle tissue. The transmission ...

anion

(Encyclopedia)anion ănˈīˌən [key], atom or group of atoms carrying a negative charge. The charge results because there are more electrons than protons in the anion. Anions can be formed from nonmetals by reduc...