Radium: the essentials

Pure metallic radium is brilliant white when freshly prepared, but blackens on exposure to air, probably due to formation of the nitride. It exhibits luminescence, as do its salts; it decomposes in water and is somewhat more volatile than barium. Radium imparts a carmine red colour to a flame.

Radium emits α, β, and γ rays and when mixed with beryllium produces neutrons. Inhalation, injection, or body exposure to radium can cause cancer and other body disorders. alkaline earth metal, white but tarnishes black upon exposure to air, luminesces, decomposes in water, emits radioactive radon gas, disintegrated radioactively until it reaches stable lead, radiological hazard, α, β, and γ emitter, exposure to radium can cause cancer and other body disorders. Radium is over a million times more radioactive than the same mass of uranium.

Radium paint was used in the mid 1900s to paint the hands and numbers of some clocks and watches. The paint was composed of radium salts and a phosphor and glowed in the dark. Image adapted with permission from Prof James Marshall's (U. North Texas, USA) Walking Tour of the elements CD.

Radium: historical information

Radium was discovered by Pierre and Marie Curie in 1898 at France. Origin of name: from the Latin word "radius" meaning "ray".

Radium was discovered in 1898 by Marie and Pierre Curie in pitchblende (or uraninite) from North Bohemia. The element was isolated in 1911 by Mme. Curie and Debierne by the electrolysis of a solution of pure radium chloride, employing a mercury cathode. On distillation in an atmosphere of hydrogen this amalgam yielded the pure metal.

Radium around us Read more »

Radium has no biological role.

Radium is found naturally in uranium ores such as pitchblende (mostly UO2). One tonne of pitchblende might yield about 0.15 g of radium. Ores containing radium are found in Zaire, Australia, Canada, and USA (New Mexico, Utah, and in small amounts in carnotite sands from Colorado). Recovery is costly. Some estimates suggest that every square kilometre of soil to a depth of a 40 cm contains about 1 g of radium.

Abundances for cobalt in a number of different environments. More abundance data »
Location ppb by weight ppb by atoms Links
Universe (no data) (no data) Chemical elements abundance by weight in the universe on a miniature periodic table spark table
Crustal rocks 0.00010 0.00001 Chemical elements abundance by weight in the earth's crust on a miniature periodic table spark table
Human 0.000001 ppb by weight 0.00000003 atoms relative to C = 1000000 Chemical elements abundance by weight in humans on a miniature periodic table spark table

Physical properties Read more »

Heat properties Read more »

Crystal structure Read more »

The solid state structure of radium is: bcc (body-centred cubic).

Radium: orbital properties Read more »

Radium atoms have 88 electrons and the shell structure is The ground state electronic configuration of neutral Radium is [Rn].7s2 and the term symbol of Radium is 1S0.


Isolation: all isotopes of radium are radioactive and there is only ever any need to make radium metal on very small scales for research purposes. Radium is extremely scarce but found in uranium ores such as pitchblende at slightly more than 1g in 10 tonnes of ore. It may be made on very small scale by the electrolysis of molten radium chloride, RaCl2. This was first done using a mercury cathode, which gave radium amalgam. The metal was obtained by distillation away from the amalgam.

cathode: Ra2+(l) + 2e- → Ra

anode: Cl-(l) → 1/2Cl2 (g) + e-

Radium isotopes Read more »

Table. Stables isotopes of cobalt.
Isotope Mass
(atom %)
spin (I)
moment (μ/μN)

WebElements Shop

You can buy periodic table posters, mugs, T-shirts, fridge magnets, games, molecular models, and more at the WebElements shop