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Tm

(Encyclopedia)Tm, chemical symbol for the element thulium. ...

resonance, in chemistry

(Encyclopedia)resonance, in chemistry: see chemical bond. ...

Le Châtelier's principle

(Encyclopedia)Le Châtelier's principle, chemical principle that states that if a system in equilibrium is disturbed by changes in determining factors, such as temperature, pressure, and concentration of components...

activation energy

(Encyclopedia)CE5 Energy profile of an exothermic reaction: Although the total energy of the products is less than that of the reactants, the activation energy must be added to weaken or break existing bonds bef...

Silurian period

(Encyclopedia)Silurian period sĭlo͝orˈēən, sī– [key] [from the Silures, ancient tribe of S Wales, where the period was first studied; named by the British geologist R. I. Murchison], third period of the Pal...

designer drug

(Encyclopedia)designer drug, chemical substance synthesized in a laboratory that is intended to have effects similar to those of a drug that is a controlled substance, such as methamphetamine, marijuana, LSD, or an...

CN (tear gas)

(Encyclopedia)CN, ordinary tear gas. The chemical name for CN is chloroacetophenone. ...

Lahontan, Lake

(Encyclopedia)Lahontan, Lake ləhŏnˈtən [key], extinct lake of W Nev. and NE Calif. It was formed by heavy precipitation caused by the Pleistocene glaciers and with Lake Bonneville (see under Bonneville Salt Fla...

Larnaca

(Encyclopedia)Larnaca lärˈnəkə [key], town (1992 pop. 43,622), SE Cyprus, on Larnaca Bay. It is a port and district administrative center. Chemicals, refined oil, and salt are important products. The modern sec...

Ledoux, Claude Nicolas

(Encyclopedia)Ledoux, Claude Nicolas klōd nēkôläˈ lədo͞oˈ [key], 1736–1806, French architect. He built palaces and various public buildings, among them the tollhouses (barrières) around Paris (1784). His...