Everything about Radium totally explained
Radium is a radioactive
chemical element which has the symbol
Ra and
atomic number 88. Its appearance is almost pure white, but it readily
oxidizes on exposure to air, turning black. Radium is an
alkaline earth metal that's found in trace amounts in
uranium ores. It is extremely
radioactive. Its most stable
isotope,, has a
half-life of 1602 years and decays into
radon gas.
Notable characteristics
The heaviest of the
alkaline earth metals, radium is intensely radioactive and resembles
barium in its chemical behavior. This metal is found in tiny quantities in the uranium ore
pitchblende, and various other uranium
minerals. Radium preparations are remarkable for maintaining themselves at a higher
temperature than their surroundings, and for their radiations, which are of three kinds:
alpha particles,
beta particles, and
gamma rays. Radium also produces
neutrons when mixed with
beryllium.
When freshly prepared, pure radium metal is brilliant white, but blackens when exposed to air (probably due to
nitride formation). Radium is
luminescent (giving a faint blue color), reacts violently with
water and
oil to form
radium hydroxide and is slightly more volatile than
barium. The normal phase of radium is a solid.
Applications
Some of the few practical uses of radium are derived from its radioactive properties. More recently discovered
radioisotopes, such as and, are replacing radium in even these limited uses because several of these isotopes are more powerful emitters, safer to handle, and available in more concentrated form.
When mixed with
beryllium it's a
neutron source for
physics experiments.
Historical uses
Radium was formerly used in
self-luminous paints for watches, nuclear panels, aircraft switches, clocks, and instrument dials. More than 100 former
watch dial painters who used their lips to shape the paintbrush died from the radiation from the radium that had become stored in their bones. Soon afterward, the adverse effects of radioactivity became widely known. Radium was still used in dials as late as the 1950s. Although
tritium's beta radiation is potentially dangerous if ingested, it has replaced radium in these applications.
During the 1930s it was found that workers' exposure to radium by handling
luminescent paints caused serious health effects which included sores,
anemia and
bone cancer. This use of radium was stopped soon afterward. This is because radium is treated as
calcium by the body, and deposited in the bones, where radioactivity degrades
marrow and can mutate bone cells. The litigation and ultimate deaths of five "
Radium Girl" employees who had used radium-based
luminous paints on the dials of watches and clocks had a significant impact on the formulation of
occupational disease labor law.
Radium was also put in some foods for taste and as a preservative, but also exposed many people to radiation. Radium was once an additive in products like toothpaste, hair creams, and even food items due to its supposed curative powers. Such products soon fell out of vogue and were prohibited by authorities in many countries, after it was discovered they could have serious adverse health effects. (See for instance
Radithor.)
Spas featuring radium-rich water are still occasionally touted as beneficial, such as those in
Misasa, Tottori,
Japan.
Radium (usually in the form of
radium chloride) is used in
medicine to produce
radon gas which in turn is used as a
cancer treatment. The isotope is currently under investigation for use in
medicine as
cancer treatment of bone
metastasis.
History
Radium (
Latin radius, ray) was
discovered by
Marie Skłodowska-Curie and her husband
Pierre in 1898 in pitchblende from North
Bohemia, in the Czech Republic (area around
Jáchymov). While studying pitchblende the Curies removed
uranium from it and found that the remaining material was still
radioactive. They then separated out a radioactive mixture consisting mostly of
barium which gave a brilliant green flame color and
crimson carmine spectral lines which had never been documented before. The Curies announced their discovery to the
French Academy of Sciences on
26 December 1898.
In 1902, radium was isolated as a pure
metal by Curie and
André-Louis Debierne through the
electrolysis of a pure radium
chloride solution by using a
mercury cathode and
distilling in an atmosphere of
hydrogen gas.
Historically the decay products of radium were known as radium A, B, C, etc. These are now known to be isotopes of other elements as follows:
|
Isotope |
| Radium emanation |
222Rn |
| Radium A |
218Po |
| Radium B |
214Pb |
| Radium C |
214Bi |
| Radium C1 |
214Po |
| Radium C2 |
210Tl |
| Radium D |
210Pb |
| Radium E |
210Bi |
| Radium F |
210Po |
On
February 4,
1936 radium E became the first
radioactive element to be made synthetically.
One unit for radioactivity, the non-
SI curie, is based on the radioactivity of
226Ra (see
Radioactivity).
Occurrence
Radium is a
decay product of uranium and is therefore found in all uranium-bearing
ores. Radium was originally acquired from
pitchblende ore from
Joachimsthal, Bohemia (One
metric ton of pitchblende yields 0.0001
grams of radium).
Carnotite sands in
Colorado provide some of the element, but richer ores are found in the
Democratic Republic of the Congo and the
Great Lakes area of
Canada, and can also be extracted from uranium processing waste. Large uranium deposits are located in
Ontario,
New Mexico,
Utah,
Virginia,
Australia, and in other places.
Compounds
Its
compounds color flames
crimson carmine (rich red or crimson color with a shade of purple) and give a characteristic
spectrum. Due to its geologically short
half life and intense radioactivity, radium compounds are quite rare, occurring almost exclusively in uranium ores.
See also .
Isotopes
Radium has 25 different known
isotopes, four of which are found in nature, with
226Ra being the most common.
223Ra,
224Ra,
226Ra and
228Ra are all generated in the decay of either
U or
Th.
226Ra is a product of
238U decay, and is the longest-lived isotope of radium with a
half-life of 1602 years; next longest is
228Ra, a product of
232Th breakdown, with a half-life of 6.7 years.
Radioactivity
Radium is over one million times more radioactive than the same mass of
uranium. Its decay occurs in at least seven stages; the successive main products have been studied and were called radium emanation or exradio (this is
radon), radium A (
polonium), radium B (
lead), radium C (
bismuth), etc.
Radon is a heavy gas and the later products are solids. These products are themselves radioactive elements, each with an atomic weight a little lower than its predecessor.
Radium loses about 1% of its activity in 25 years, being transformed into elements of lower atomic weight with
lead being the final product of disintegration.
The SI unit of radioactivity is the
becquerel (Bq), equal to one disintegration per second. The
curie is a non-SI unit defined as that amount of radioactivity which has the same disintegration rate as 1 gram of Ra-226 (3.7 x 10
10 disintegrations per second, or 37 GBq).
Safety
Handling of radium has been blamed for
Marie Curie's premature death.
Radium is highly radioactive and its decay product, radon gas, is also radioactive. Since radium is chemically similar to calcium, it has the potential to cause great harm by replacing it in bones. Inhalation, injection, ingestion or body exposure to radium can cause cancer and other disorders. Stored radium should be ventilated to prevent accumulation of radon.
Emitted energy from the decay of radium ionizes gases, affects photographic plates, causes sores on the skin, and produces many other detrimental effects.Further Information
Get more info on 'Radium'.
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