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nitrate

(Encyclopedia)nitrate, chemical compound containing the nitrate (NO3) radical. Nitrates are salts or esters of nitric acid, HNO3, formed by replacing the hydrogen with a metal (e.g., sodium or potassium) or a radic...

Graham, Thomas

(Encyclopedia)Graham, Thomas, 1805–69, Scottish chemist, best known for research in diffusion in both gases and liquids that led to his formulation of Graham's law. His discovery that certain substances (e.g., gl...

lignin

(Encyclopedia)lignin lĭgˈnĭn [key], a highly polymerized and complex chemical compound especially common in woody plants. The cellulose walls of the wood become impregnated with lignin, a process called lignific...

photochemistry

(Encyclopedia)photochemistry, study of chemical processes that are accompanied by or catalyzed by the emission or absorption of visible light or ultraviolet radiation. A molecule in its ground (unexcited) state can...

chelating agents

(Encyclopedia)chelating agents kēˈlātĭng [key]. Certain organic compounds are capable of forming coordinate bonds (see chemical bond) with metals through two or more atoms of the organic compound; such organic ...

Dasht-e Kavir

(Encyclopedia)Dasht-e Kavir däsht-ēkävērˈ [key], great salt desert, c.500 mi (800 km) long and c.200 mi (320 km) wide, SE of the Elburz Mts., N central Iran. It is a huge basin of interior drainage named after...

saturation, of an organic compound

(Encyclopedia)saturation, of an organic compound, condition occurring when its molecules contain no double or triple bonds and thus cannot undergo addition reactions. For example, ethane (H3C–CH3) is a saturated ...

Artemovsk

(Encyclopedia)Artemovsk ərtyôˈməfsk [key], Ukr. Artemivsk, city (1989 pop. 90,000), in Ukraine. An industrial center of the Donets Basin, it produces metals, mining equipment, glass, bricks, and chemicals. Near...

Mariupol

(Encyclopedia)Mariupol zhdänˈəf [key], city (1989 pop. 520,000), SE Ukraine, on the Sea of Azov and at the mouth of the Kalmius River. A seaport and railroad terminus, Mariupol is also an iron and steel center w...

sulfur dioxide

(Encyclopedia)sulfur dioxide, chemical compound, SO2, a colorless gas with a pungent, suffocating odor. It is readily soluble in cold water, sparingly soluble in hot water, and soluble in alcohol, acetic acid, and ...