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organometallic chemistry

(Encyclopedia)organometallic chemistry, the reactions and use of a class of compounds (R-M) that contain a covalent bond between carbon and metal. They are prepared either by direct reaction of the metal with an or...

electronegativity

(Encyclopedia)electronegativity ĭlĕkˌtrōnĕgətĭvˈətē [key], in chemistry, tendency for an atom to attract a pair of electrons that it shares with another atom (see chemical bond). For example, the molecule...

Sverdrup, Harald Ulrik

(Encyclopedia)Sverdrup, Harald Ulrik häˈräl o͞olˈrĭk svĕrˈdro͝op [key], 1888–1957, Norwegian oceanographer and meteorologist. He was in charge of the scientific work on the Maud for Amundsen's arctic exp...

weather satellite

(Encyclopedia)weather satellite, artificial satellite used to gather data on a global basis for improvement of weather forecasting. Information includes cloud cover, storm location, temperature, and heat balance in...

cation

(Encyclopedia)cation kătˌīˈən [key], atom or group of atoms carrying a positive charge. The charge results because there are more protons than electrons in the cation. Cations can be formed from a metal by oxi...

Venus's-flytrap

(Encyclopedia)Venus's-flytrap, insectivorous or carnivorous bog plant (Dionaea muscipula) native to the Carolina savannas and now widely cultivated as a novelty. The leaves, borne in a low rosette, resemble bear tr...

custard-apple

(Encyclopedia)custard-apple, common name for members of the Annonaceae, a family of shrubs, woody vines, and small trees of the tropics. The custard-apples (Annona squamosa and A. reticulata) and other members of t...

Engelmann, George

(Encyclopedia)Engelmann, George ĕngˈəlmən [key], 1809–84, American physician and botanist, b. Frankfurt-am-Main, Germany, educated at the universities of Heidelberg and Würzburg (M.D., 1831). Emigrating to A...

Enzio

(Encyclopedia)Enzio ānˈtsō [key], c.1220–72, king of Sardinia, illegitimate son of Holy Roman Emperor Frederick II. He married a Sardinian heiress and was made king of Sardinia by his father. In the wars betwe...

Palisades

(Encyclopedia)Palisades, cliffs along the west bank of the Hudson River, NE N.J. and SE N.Y., extending from N of Jersey City, N.J., to the vicinity of Piermont, N.Y., with a general altitude of from 350 ft to 550 ...