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sulfate

(Encyclopedia)sulfate, chemical compound containing the sulfate (SO4) radical. Sulfates are salts or esters of sulfuric acid, H2SO4, formed by replacing one or both of the hydrogens with a metal (e.g., sodium) or a...

superconductivity

(Encyclopedia)superconductivity, abnormally high electrical conductivity of certain substances. The phenomenon was discovered in 1911 by Heike Kamerlingh Onnes, who found that the resistance of mercury dropped sudd...

manganese

(Encyclopedia)manganese măngˈgənēs, mănˈ– [key] [Lat.,=magnet], metallic chemical element; symbol Mn; at. no. 25; at. wt. 54.93805; m.p. about 1,244℃; b.p. about 1,962℃; sp. gr. 7.2 to 7.45, depending o...

radium

(Encyclopedia)radium rāˈdēəm [key] [Lat. radius=ray], radioactive metallic chemical element; symbol Ra; at. no. 88; mass number of most stable isotope 226; m.p. 700℃; b.p. 1,140℃; sp. gr. about 6.0; valence...

roof

(Encyclopedia)roof, overhead covering of a building with its framework support. Various methods of construction, such as are suited to different climates, have diversified exterior and interior architectural effect...

Trentino–Alto Adige

(Encyclopedia)Trentino–Alto Adige trāntēˈnō-älˈtō äˈdējā [key], region (1991 est. pop. 890,360), 5,256 sq mi (13,613 sq km), N Italy, bordering on Switzerland in the northwest and on Austria in the nor...

Hadid, Dame Zaha

(Encyclopedia)Hadid, Dame Zaha, 1950–2016, British architect, b. Baghdad, studied American Univ., Beirut (1968–71), Architectural Association School, London (grad. 1977). A partner in Rem Koolhaas's Office for ...

silver

(Encyclopedia)silver, metallic chemical element; symbol Ag [Lat. argentum]; at. no. 47; at. wt. 107.8682; m.p. 961.93℃; b.p. 2,212℃; sp. gr. 10.5 at 20℃; valence +1 or +2. Pure silver is nearly white, lustrou...

Basque Country

(Encyclopedia)Basque Country băsk, bäsk [key], Basque Euzkadi, Span. País Vasco, autonomous communit...

metal

(Encyclopedia)metal, chemical element displaying certain properties by which it is normally distinguished from a nonmetal, notably its metallic luster, the capacity to lose electrons and form a positive ion, and th...