Adjacent Words

radium definitions

	Tweet

WordNet (r) 3.0 (2005)

n
1: an intensely radioactive metallic element that occurs in minute amounts in uranium ores [syn: radium, Ra, atomic number 88]

Merriam Webster's

noun Usage: often attributive Etymology: New Latin, from Latin radius ray Date: 1899 an intensely radioactive brilliant white metallic element that resembles barium chemically, occurs in combination in minute quantities in minerals (as pitchblende or carnotite), emits alpha particles and gamma rays to form radon, and is used chiefly in luminous materials and in the treatment of cancer — see element table

Dictionary of the Elements

radium
Symbol: Ra
Atomic number: 88
Atomic weight: (226)
Radioactive metallic transuranic element, belongs to group 2 of the periodic table. Most stable isotope, Ra-226 has a half-life of 1602 years, which decays into radon. Isolated from pitchblende in 1898 Marie and Pierre Curie.

Oxford Reference Dictionary

n. Chem. a radioactive metallic element orig. obtained from pitchblende etc., used esp. in luminous materials and in radiotherapy. Usage: Symb.: Ra. Phrases and idioms: radium bomb a container holding a large quantity of radium and used in radiotherapy as a source of gamma rays. radium emanation = RADON. radium therapy the treatment of disease by the use of radium. Etymology: L radius ray

Webster's 1913 Dictionary

Radium Ra`di*um, n. [NL., fr. L. radius ray.] (Chem.) An intensely radioactive metallic element found (combined) in minute quantities in pitchblende, and various other uranium minerals. Symbol, Ra; atomic weight, 226.4. Radium was discovered by M. and Mme. Curie, of Paris, who in 1902 separated compounds of it by a tedious process from pitchblende. Its compounds color flames carmine and give a characteristic spectrum. It resembles barium chemically. Radium preparations are remarkable for maintaining themselves at a higher temperature than their surroundings, and for their radiations, which are of three kinds: alpha rays, beta rays, and gamma rays (see these terms). By reason of these rays they ionize gases, affect photographic plates, cause sores on the skin, and produce many other striking effects. Their degree of activity depends on the proportion of radium present, but not on its state of chemical combination or on external conditions.The radioactivity of radium is therefore an atomic property, and is explained as result from a disintegration of the atom. This breaking up occurs in at least seven stages; the successive main products have been studied and are called radium emanation or exradio, radium A, radium B, radium C, etc. (The emanation is a heavy gas, the later products are solids.) These products are regarded as unstable elements, each with an atomic weight a little lower than its predecessor. It is possible that lead is the stable end product. At the same time the light gas helium is formed; it probably consists of the expelled alpha particles. The heat effect mentioned above is ascribed to the impacts of these particles. Radium, in turn, is believed to be formed indirectly by an immeasurably slow disintegration of uranium.

Collin's Cobuild Dictionary

Radium is a radioactive element which is used in the treatment of cancer.

Foolish Dictionary

A radiant radiator, redolent of ranging radial rays of radio-activity, raised to radical rates and regarded as a ruthless rake-off in the reign of riches within the arrayed radius of a raging, raving and raided race.

Moby Thesaurus

acid, actual cautery, americium, astatine, atomic cocktail, berkelium, brand, brand iron, branding iron, caustic, cauter, cauterant, cauterizer, cautery, cobalt, corrosive, curium, einsteinium, electrocautery, escharotic, fermium, francium, hahnium, hot iron, lunar caustic, mendelevium, mordant, moxa, neptunium, plutonium, polonium, potential cautery, promethium, protactinium, radiocalcium, radiocarbon, radioelement, radioiodine, radioisotope, radiosodium, radon, tagged element, technetium, tracer, uranium