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radium

American  
[rey-dee-uhm] / ˈreɪ di əm /

noun

  1. Chemistry.  a highly radioactive metallic element whose decay yields radon gas and alpha rays. Ra; 226; 88.

  2. a lustrous rayon or silk fabric constructed in plain weave and used in women's apparel, lining, and drapery.


radium British  
/ ˈreɪdɪəm /

noun

    1. a highly radioactive luminescent white element of the alkaline earth group of metals. It occurs in pitchblende, carnotite, and other uranium ores, and is used in radiotherapy and in luminous paints. Symbol: Ra; atomic no: 88; half-life of most stable isotope, 226 Ra: 1620 years; valency: 2; relative density: 5; melting pt: 700°C; boiling pt: 1140°C

    2. ( as modifier )

      radium needle

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

radium Scientific  
/ rādē-əm /
  1. A rare, bright-white, highly radioactive element of the alkaline-earth group. It occurs naturally in very small amounts in ores and minerals containing uranium, and it is naturally luminescent. Radium is used as a source of radon gas for the treatment of disease and as a neutron source for scientific research. Its most stable isotope is Ra 226 with a half-life of 1,622 years. Atomic number 88; melting point 700°C; boiling point 1,737°C; valence 2.

  2. See Periodic Table


radium Cultural  
  1. A naturally occurring radioactive chemical element. Its symbol is Ra.


Discover More

Radium was discovered by the chemists Marie and Pierre Curie.

Etymology

Origin of radium

1895–1900; < New Latin, equivalent to Latin rad ( ius ) ray ( radius ) + -ium -ium

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

In research published on October 23 in Science, the team precisely measured the energy of electrons orbiting a radium atom that was chemically bound to a fluoride atom, forming radium monofluoride.

From Science Daily

It contains radium that decays into radon gas, which is radioactive and can cause cancer.

From Barron's

Rob Caunter, who finally retired from the fish market this year, is just finishing his radium treatment for prostate cancer.

From BBC

The researchers found that, even years later, the tissue and shells of mussels contained radium that could be traced to wastewater from fracking in the Marcellus Shale.

From Science Daily

The system can be adapted to detect other similar contaminants in water, including cadmium, copper, lithium, barium, cesium, and radium, Ranno says.

From Science Daily