POTASSIUM

(Lat.), n. n. Po2t-a2s(a3s)'sia-usm(u<m). Fr., p. Ger., Kalium. Sp., potasio, potaso [Mex. Ph.]. A metallic element discovered in 1807 by Sir Humphry Davy; a silvery-white solid, at ordinary temperatures waxy and ductile, at C. brittle and breaking with a crystalline fracture. It melts at 62'5 C. to a liquid resembling mercury in appearance; and from this liquid, when quickly cooled, the metal may be obtained in the form of octaedral crystals. It boils at a red heat, with the production of green vapor. It has a strong affinity for oxygen, abstracting this element from nearly all its compounds even at ordinary temperatures. It accordingly decomposes water with the liberation of hydrogen and the evolution of so much heat as to produce combustion; and on exposure to the air it tarnishes, from the formation of p. oxide. In its chemical relations it closely resembles sodium, lithium, rubidium, caesium, and ammonium. It is univalent. Atomic weight, 39: sp. gr., 0-865; symbol, K or Ka (from Kalium). [B.] Acid p. antimonate. Lat., kali stibicrim (seu stibioso-stibicum) acid.um. Fr., antimoniate acide de pota e. Ger.. saures an timons aures Kalium. A compound of p. antimonate with antimonic acid. Several such compounds are known, some of which have been used in medicine under the name of an tim onium diaphoreticum ablutum (seu lavatum), etc. [B.] Acid p. carbonate. See P. bicarbonate. Acid p. chromate. See P. dichromate.-A.cid p. disulphate. See P. pyrosulphate. Acid p. met antimonate. Ger., Kalium hydro met an tim on at. A crystalline substance, KjH3Sb2- O, no; Oa, not; Os, whole; Th, thin; Th", the; U, like oo in too; 332 [s. 319]