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caustic

(Encyclopedia)caustic, any strongly corrosive chemical substance, especially one that attacks organic matter. A caustic alkali is a metal hydroxide, especially that of an alkali metal; caustic soda is sodium hydrox...

lanthanum

(Encyclopedia)lanthanum lănˈthənəm [key] [Gr.,=to lie hidden], metallic chemical element; symbol La; at. no. 57; at. wt. 138.90547; m.p. about 920℃; b.p. about 3,460℃; sp. gr. 6.19 at 25℃; valence +3. Lan...

lutetium

(Encyclopedia)lutetium, formerly lutecium both: lo͞otēˈshēəm [key], metallic chemical element; symbol Lu; atomic number 71; at. wt. 174.9668; m.p. about 1,663℃; b.p. about 3,395℃; sp. gr. 9.835 at 25℃; v...

Gay-Lussac, Joseph Louis

(Encyclopedia)Gay-Lussac, Joseph Louis zhôzĕfˈ lwē gā-lüsäkˈ [key], 1778–1850, French chemist and physicist. He was professor in Paris at the Sorbonne, at the Polytechnic School, and at the Jardin des Pla...

sodium

(Encyclopedia)sodium, a metallic chemical element; symbol Na [Lat. natrium]; at. no. 11; at. wt. 22.98977; m.p. 97.81℃; b.p. 892.9℃; sp. gr. 0.971 at 20℃; valence +1. Sodium is a soft, silver-white metal. Ext...

potassium

(Encyclopedia)potassium pətăsˈēəm [key], a metallic chemical element; symbol K [Lat. kalium=alkali]; at. no. 19; at. wt. 39.0983; m.p. 63.25℃; b.p. 760℃; sp. gr. .862 at 20℃; valence +1. Potassium is a s...

rubidium

(Encyclopedia)rubidium ro͞obĭdˈēəm [key], metallic chemical element; symbol Rb; at. no. 37; at. wt. 85.4678; m.p. 38.89℃; b.p. 686℃; sp. gr. 1.53 at 20℃; valence +1. Rubidium is a very soft silver-white ...

carbon disulfide

(Encyclopedia)carbon disulfide, CS2, liquid organic compound; it is colorless, foul-smelling, flammable, and poisonous. It can be prepared by direct reaction of carbon, e.g., as charcoal, with sulfur. It is a widel...

Widnes

(Encyclopedia)Widnes wĭdˈnĭs [key], city (1991 pop. 55,973), Halton, NW England, on the Mersey River. It is an important alkali-processing center. Other products are paints, soap, pharmaceuticals, and steel good...

cesium

(Encyclopedia)cesium sēˈzēəm [key] [Lat.,=bluish gray], a metallic chemical element; symbol Cs; at. no. 55; at. wt. 132.90545; m.p. 28.4℃; b.p. 669.3℃; sp. gr. 1.873 at 20℃; valence +1. Cesium is a ductil...