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alum

(Encyclopedia)alum ălˈəm [key], any one of a series of isomorphous double salts that are hydrated sulfates of a univalent cation (e.g., potassium, sodium, ammonium, cesium, or thallium) and a trivalent cation (e...

Freeport, cities, United States

(Encyclopedia)Freeport. 1 City (2020 pop. 23,973), seat of Stephenson co., NW Ill., on the Pecatonica River; inc. 1850. It is a trade and manufacturing center in a ...

water supply

(Encyclopedia)water supply, process or activity by which water is provided for some use, e.g., to a home, factory, or business. The term may also refer to the supply of water provided in this way. In the United Sta...

electromotive series

(Encyclopedia)electromotive series, list of metals whose order indicates the relative tendency to be oxidized, or to give up electrons (see oxidation and reduction); the list also includes the gas hydrogen. The ele...

rare-earth metals

(Encyclopedia)rare-earth metals, in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, whi...

hafnium

(Encyclopedia)hafnium hăfˈnēəm [key], metallic chemical element; symbol Hf; at. no. 72; at. wt. 178.49; m.p. about 2,227℃; b.p. 4,602℃; sp. gr. 13.31 at 20℃; valence +4. Hafnium is a lustrous, ductile, si...

phosphate

(Encyclopedia)phosphate, salt or ester of phosphoric acid, H3PO4. Because phosphoric acid is tribasic (having three replaceable hydrogen atoms), it forms monophosphate, diphosphate, and triphosphate salts in which ...

mantle

(Encyclopedia)mantle, portion of the earth's interior lying beneath the crust and above the core. No direct observation of the mantle, or its upper boundary, has been made; its boundaries have been determined solel...

Kuril Islands

(Encyclopedia)Kuril Islands kyo͝orˈēlz, kyo͝orēlzˈ [key], Jap. Chishima-Retto, Rus. Kurilskiye Ostrova, island chain, c.6,020 sq mi (15,590 sq km), Sakhalin region, E Russia. They stretch c.775 mi (1,250 km) ...

Henderson

(Encyclopedia)Henderson. 1 City (2020 pop. 27,801), seat of Henderson co., NW Ky., on the Ohio River, in an oil, coal, tobacco, corn, and livestock area; founded ...