7440-14-4 Usage
Description
Radium has the symbol Ra and atomic number 88. Its
atomic weight is 226.0254 g/mol. Radium is an alkaline earth metal that is found in trace amounts in uranium
ores. Its most stable isotope, 226Ra, has a half-life of
1602 years and decays into radon gas.
The heaviest of the alkaline earth elements, 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.When freshly prepared, pure radium metal is almost pure white, but blackens when exposed to air (probably due to nitride formation). Radium is luminescent when struck by electromagnetic radiation of the proper wavelength (giving a faint blue color). It reacts violently with water to form radium hydroxide and is slightly more volatile than barium. The normal phase of radium is a solid. Since all the isotopes of radium are radioactive and short-lived on the geological time scale, any primeval radium would have disappeared long ago. Therefore, radium occurs naturally only as a disintegration product in the three natural radioactive decay series (Thorium, Uranium, and Actinium series). Radium-226 is a member of the uranium decay series. Its parent is Thorium-230 and its daughter Radon-222. Radium is a decay product of uranium and is therefore found in all uranium-bearing ores. (One ton of Pitchblende yields one seventh of a gram of radium). Radium was originally acquired from pitchblende ore from the Czech Republic. Carnotite (K2(UO2)2(VO4)2·3H2O) sands in Colorado provide some of the element, but richer ores are found in the Democratic Republic of Congo and the Great Lakes area of Canada. Radium can also be extracted from uranium processing waste.
Chemical Properties
Different sources of media describe the Chemical Properties of 7440-14-4 differently. You can refer to the following data:
1. Brilliant-white solid. Luminescent, turns black on exposure
to air. Soluble in water with evolution of hydrogen;
forms water-soluble compounds. Decays by emis-
sion of α-, β-, and γ-radiation. Bone-seeking when
taken into the body.
2. Radium (Ra) is a radioactive element, found
naturally occurring in the environment. Ra is a silvery-
white-metallic solid @ 25℃; it tarnishes black when
exposed to air. It is an alkaline earth metal; there are 33
isotopes, all of them are unstable. Radium is commonly
available as radium bromide (RaBr2 ) or radium chloride
(RaCl2 ).
Physical properties
Radium is the last element in group 2 and is very similar to the other alkali earth metals,which makes it the largest and heaviest element in the group. It particularly resembles barium,which is just above it in group 2 of the periodic table. Radium is a bright white radioactiveluminescent alkali earth metal that turns black when exposed to air. Its melting point is700°C, its boiling point is 1,140°C, and its density is approximately 5.0 g/cm3.
Isotopes
Different sources of media describe the Isotopes of 7440-14-4 differently. You can refer to the following data:
1. There are no stable isotopes of radium. Radium has 25 known radioisotopes,ranging from Ra-206 to Ra-230. Their half-lives range from a fraction of a second tohundreds of years. Radium-226 was discovered by the Curies and has a half-life ofabout 1630 years. Ra-226 is the most abundant isotope, and thus, Ra-226 is used todetermine radium’s atomic mass.Various radium isotopes are derived through a series of radioactive decay processes. Forexample, Ra-223 is derived from the decay of actinium. Ra-228 and Ra-224 are the resultof the series of thorium decays, and Ra-226 is a result of the decay of the uranium series.
2. Radium (Ra) has no stable isotopes. A standard atomic mass cannot be given (but is usually given as 226.0 g/mol). The longest lived, and most common, isotope of radium is 226Ra that occurs in the disintegration chain of 238U (often referred to as the radiumseries). Radium (Ra) has 33 different known isotopes, four of which are found in nature, with 226Ra being the most common. 223Ra, 224Ra, 226Ra and 228Ra are all generated naturally in the decay of either Uranium (U) or Thorium (Th). 226Ra is a product of 238U decay, and is the longestlived isotope of radium with a half-life of 1602 years. The next longest is 228Ra, a product of 232Th breakdown, with a half-life of 5.75 years.
Origin of Name
Radium’s name is derived from the Latin word radius, which means
“ray.
Occurrence
Radium is the 85th most abundant element found in the Earth’s crust. Radium is found inthe uranium ores pitchblende and chalcolite, which are both very radioactive. Radium metalexists to the extent of only one part to every three million parts of the uranium ore (pitchblende). Only about one gram of radium is found in every seven or eight tons of uraniumore. This scarcity seems to be the reason that only about five pounds of uranium are producedeach year in the entire world. Uranium ores are found in the states of Utah, New Mexico, andColorado in the United States and in Canada, the Czech Republic, Slovakia, Russia, Zaire,and France.
History
Different sources of media describe the History of 7440-14-4 differently. You can refer to the following data:
1. Radium (Latin radius, ray) was discovered by Pierre
Curie, Marie Curie, and an assistant, G. Be′mont. This
occurred after Marie Curie had observed that the radioactivity
of pitchblende was four or five times greater
than that of the uranium it contained and was not fully
explained on the basis of radioactive polonium, which
she had just discovered in pitchblende residues originating
from North Bohemia, in the Czech Republic.
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 that
produced a brilliant green flame color and crimsoncarmine
spectral lines that had never been documented
before. The Curies announced their discovery to the
French Academy of Sciences on 26 December 1898.
In 1910, radium was isolated as a pure metal by Curie
and Debierne through the electrolysis of a pure radium
chloride solution by using a mercury cathode and
distilling it in an atmosphere of hydrogen gas. The separation
was followed by the increase in intensity of the
new lines in the ultraviolet spectrum and by a steady
increase in the apparent atomic weight of the material
until a value of 225.18 was obtained, remarkably close
to the accepted value of 226.03. By 1902, 0.1 g of pure
radium chloride was prepared by refining several tons
of pitchblende residues, and by 1910 Marie Curie and
Andre′-Louis Debierne had isolated the metal itself.
Radium was first industrially produced in the beginning
of the twentieth century by Birac, a subsidiary
company of UMHK in its Olen plant in Belgium. This
company offered to Marie Curie her first gram of
radium. Historically the decay products of radium
were known as radium A, B, C, etc.
2. Curie in the pitchblende or uraninite of North Bohemia
(Czech Republic), where it occurs. There is about 1 g of radium
in 7 tons of pitchblende. 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. Originally, radium was obtained from
the rich pitchblende ore found at Joachimsthal, Bohemia. The
carnotite sands of Colorado furnish some radium, but richer
ores are found in the Republic of Congo-Kinshasa and the
Great Bear Lake region of Canada. Radium is present in all
uranium minerals, and could be extracted, if desired, from the
extensive wastes of uranium processing. Large uranium deposits
are located in Ontario, New Mexico, Utah, Australia,
and elsewhere. Radium is obtained commercially as the bromide
or chloride; it is doubtful if any appreciable stock of the
isolated element now exists. The pure metal 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. It is a member of the alkaline-earth group
of metals. Radium imparts a carmine red color to a flame.
Radium emits alpha, beta, and gamma rays and when mixed
with beryllium produce neutrons. One gram of 226Ra undergoes
3.7 × 1010 disintegrations per s. The curie (Ci) is defined
as that amount of radioactivity which has the same disintegration
rate as 1 g of 226Ra. Thirty-six isotopes are now known;
radium 226, the common isotope, has a half-life of 1599 years.
One gram of radium produces about 0.0001 mL (stp) of emanation,
or radon gas, per day. This is pumped from the radium
and sealed in minute tubes, which are used in the treatment of
cancer and other diseases. One gram of radium yields about
4186 kJ per year. Radium is used in producing self-luminous paints, neutron sources, and in medicine for the treatment of
cancer. Some of the more recently discovered radioisotopes,
such as 60Co, are now being used in place of radium. Some of
these sources are much more powerful, and others are safer
to use. Radium loses about 1% of its activity in 25 years, being
transformed into elements of lower atomic weight. Lead
is a final product of disintegration. Stored radium should be
ventilated to prevent build-up of radon. Inhalation, injection,
or body exposure to radium can cause cancer and other body
disorders. The maximum permissible burden in the total body
for 226Ra is 7400 becquerel.
Characteristics
Radium is extremely radioactive. It glows in the dark with a faint bluish light. Radium’sradioisotopes undergo a series of four decay processes; each decay process ends with a stableisotope of lead. Radium-223 decays to Pb-207; radium-224 and radium-228decay to Pb-208;radium-226 decays to Pb-206; and radium-225 decays to Pb-209. During the decay processesthree types of radiation—alpha (α), beta (β), and gamma (γ)—are emitted.In addition to being radioactive, radium is extremely chemically reactive and forms manycompounds. These radium compounds are not only radioactive but also toxic and should behandled by experienced personnel.
Uses
Different sources of media describe the Uses of 7440-14-4 differently. You can refer to the following data:
1. Medical treatment for malignant growths, ind-
ustrial radiography, source of neutrons and radon.
2. Radium’s most important use is as a source of radiation in industry, medicine, and laboratories. The isotope radium-226, which is the most abundant of all the 25 isotopes and has ahalf-life of 1630 years, is the only useful form of the element. It is used in the medical treatment of malignant cancer growth. It kills cancer cells that have spread throughout the body.Other uses are to produce phosphorescence and fluorescence in organic compounds andfor scintillation screens on instruments used to detect radiation. Radium salts were used in thepast to paint the dials of luminous clock faces that glow in the dark.
3. In 1909, the famous Rutherford experiment used radium as an alpha source to probe the atomic structure of gold. This experiment led to the Rutherford model of the atom and revolutionized the field of nuclear physics. Radium (usually in the form of RaCl2) was used in medicine to produce radon gas which in turn was used as a cancer treatment. For example, several radon sources were used in Canada in the 1920s and 1930s. The isotope 223Ra is currently under investigation for its use in cancer treatment of bone metastasis. Some of the few practical uses of radium are derived from its radioactive properties. More recently discovered radioisotopes, such as 60Co and 137Cs 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.
Definition
Different sources of media describe the Definition of 7440-14-4 differently. You can refer to the following data:
1. Radioactive element of group IIA of
the periodic table, atomic number 88, aw 226.0254,
valence = 2. There are 14 radioactive isotopes but
only radium-226 with half-life of 1620 years is
usable. Discovered by the Curies in 1898.
2. A white radioactive luminescent metallic element of the alkaline- earth group. It has several short-lived radioisotopes and one long-lived isotope, radium-226 (half-life 1602 years). Radium is found in uranium ores, such as the oxides pitchblende and carnotite. It was formerly used in luminous paints and radiotherapy. Symbol: Ra; m.p. 700°C; b.p. 1140°C; r.d. 5 (approx. 20°C); p.n. 88; r.a.m. 226.0254 (226Ra).
3. radium: Symbol Ra. A radioactivemetallic element belonging togroup 2 (formerly IIA) of the periodictable; a.n. 88; r.a.m. 226.0254;r.d. ～5; m.p. 700°C; b.p. 1140°C. It occursin uranium ores (e.g. pitchblende).The most stable isotope isradium–226 (half-life 1602 years),which decays to radon. It is used as aradioactive source in research and, tosome extent, in radiotherapy. The elementwas isolated from pitchblendein 1898 by Marie and Pierre Curie.
Hazard
Different sources of media describe the Hazard of 7440-14-4 differently. You can refer to the following data:
1. Because radium energetically emits three types of radiation, it poses great danger to anyone handling it. In addition, it is toxic. If it is ingested in even small amounts, it replaces bone tissue, which can result in radiation sickness and death. One of the decay products of radium is the gas radon, which can seep up through the Earth s crust into basements and slab level homes. Good ventilation assures that the radon does not accumulate to the extent that would be harmful. At one time, women painted clock and watch dials with luminous radium paint that was a mixture of radium salts and zinc sulfide. They would place the small brushes between their lips and tongue to make the bristles more pointed, in order to paint fine lines with the radium paint. Over the years, they developed cancers that resulted in badly eaten-away and disfigured lips and jaws. Once the danger was known, luminous radium paint was banned for this use. Today, promethium (Pm-147), with a half-life of 2.4 years, is used for this purpose.
2. Highly toxic, emits ionizing radiation. Lead
shielding should be used in storage and handling,
adequate protective clothing and remote control
devices are essential. Destructive to living tissue.
Safety Profile
A highly radiotoxic element. 1 g produces 3.7 x 1010 disintegrations per second. Inhalation, ingestion, or bodily exposure can lead to lung cancer, bone cancer, osteitis, skin damage, and blood dyscrasias. A common air contaminant. Radum replaces calcium in the bone structure and is a source of irradation to the blood-forming organs. The ingestion of luminous dial paint prepared from radium caused death in many of the early dal painters before the hazard was fully understood. The data on these workers have been the source of many of the radation precautions and the maximum permissible levels for internal emitters that are now accepted. 226Ra is the parent of radon and the precautions described under 222Rn should be followed. 22*Ra is a member of the thorium series. It was a common constituent of luminous paints, and, whde its low beta energy was not a hazard, its daughters in the series may have been a causative agent in the deaths of the radium dal painters following World War I. It is metabolized in the same way as any other radum isotope and it is a source of thorium. The precautions recommended under ZZORn should be followed. Highly dangerous; must be kept heavily shielded and stored away from possible dissemination by explosion, flood, etc. Radation Hazard: Natural isotope 223Ra (Actinium-X, Actinium Series), T1/2 = 11.4 days, decays to radoactive 219Rn by alphas of
5.5-5.7 MeV. Natural isotope 224Ra (Thorium-X, Thorium Series), T1/2 = 3.6 days, decays to radioactive 22ORn by alphas of 5.7 MeV. Natural isotope 226Ra (Uranium Series), T1/2 = 1600 years, decays to radoactive 222Rn by alphas of 4.8 MeV. Natural isotope 22*Ra (Mesothorium = 1 , Thorium Series), T1/2 = 6.7 years, decays to radoactive 22*Ac by betas of 0.05 MeV.
Potential Exposure
Radium is not available as a pure
metal but is found in very small quantities in uranium and
thorium ores. Uranium and thorium are found in small
amounts in most rocks and soil; radium is formed when
these elements break down in the environment. One ton of
uranium ore yields only slightly more than 0.1 gm of
radium. Radium is formed from the radioactive decay; and,
as a by-product of refining these ores. Radium exists in
several isotope forms. Two of the principal radium isotopes
found in the environment are
226 Ra (radium-226) and 228 Ra
(radium-228). Radium compounds, due to their geologically
short half-life and intense radioactivity, are quite rare. A
single gram of
226 Ra produces 10 24
mm of radon (Rn)
a day. Radium’s- 226, radium’s most stable isotope has a
half-life of about 1603 to 1620 years, and remains in the
body for life. Radium, when used to produce radon gas, is
used for treating various types of cancer; in radiography of
metals; and combined with other metals, such as beryllium,
as a neutron emitting source used in research and for cali-
brating radiation instruments. Until the 1960s, radium was
a component in self-luminous paints used for watch, com-
pass, and aircraft instrument dials and other aircraft and
military instrumentation. A less dangerous radioactive
source,
60 Co (cobalt-60), replaced radium in luminous
paint. The greatest health risk from radium comes from
exposure to its radioactive decay product, radon (Rn).
Radon is common in many soils and can collect in build-
ings, including homes.
Carcinogenicity
The U.S. EPA has classified
radium as a class A carcinogen, meaning that there are
sufficient data to support a link between exposure to radium
and the development of human cancer. The α-particle radiation
associated with radium is recognized as the causative
agent for sarcomas of the bone and carcinomas of the
paranasal sinuses in humans. A study attempting to
ascertain the dose–incidence relationship for induction of
these tumors examined 1474 women employed in the U.S.
radium dial painting industry before 1930. This population
exhibited 61 known cases of bone sarcoma and 21 cases of
carcinoma of the paranasal sinuses or the mastoid air
cells. Of these individuals, the radium body burden
was known for 759, among whom there were 38 cases of bone
sarcoma and 17 head carcinomas.
Environmental Fate
Radium is released to the environment from a variety of
sources, including milling and mining operations focused on
phosphates and uranium, waste streams from factories used
to produce products containing radium, or waste byproducts
from production, such as phosphate fertilizers. The most important route of radium release into the environment is the
combustion of coal, and released radium is estimated at 150 Ci
per year (or 5.55×1012 Bq). Radium released into the atmosphere
will remain in particulate form until wet or dry deposition.
Radium adsorbs to soils, and is not expected to volatize
from soils or water due to its ionic nature. In water, radium
exists as Ra+2 and can interact with sediments and dissolve in
water, and therefore generally adsorbs to sediments at the
emission site and is not transported. Some isotopes of radium
are very short lived, but radium-226 has a half-life of
1600 years, making long-range transport more likely, though
generally only through an atmospheric route. Radium’s ionic
nature makes bioaccumulation or biomagnification unlikely.
Shipping
UN3323(does not appear in the 49CFR hazard
materials tables ) Radioactive material, Type C package,
nonfissile or fissile excepted. UN2915 Radioactive mate-
rial, Type A package nonspecial form, nonfissile or fissile-
excepted, Hazard class: 7-Radioactive material; Labels:
None. A1 and A2 values for Radium- 226 taken from
y173.435 (see also Table A-1 in 10CFR71(Appendix A): A1
(SpecialForm * ) 0.3 TBq (8.11Ci); A2 (NormalForm)
0.02TBq (0.541Ci))
Toxicity evaluation
The radioactive properties of radium are the greatest concern and
overwhelm all others. All radioactive materials may cause harm when decay particles are released; they disrupt many critical cell
functions, includingDNA replication. Radioactive materials may
also produce toxicity not related to their radioactive behavior.
Like barium compounds, radium enters teeth and bones,
altering growth and causing them to be weak and brittle.
Incompatibilities
Metallic radium is highly chemically
reactive. It forms compounds that are very similar to barium
compounds, making separation of the two elements
difficult. On contact with water, radium forms flammable
hydrogen gas.
Waste Disposal
Radioactive material consid-
ered waste and must be retained in containers for disposi-
tion by the authorizing institution. Drain disposal is
prohibited. It is the responsibility of the operating institu-
tion to arrange for the proper disposal of all forms of any
radioisotopes. The use, storage, transportation, labeling,
and disposal of radioactive material are regulated through
the Nuclear Regulatory Commission (NRC) using 10 CFR
(Code of Federal Regulations) as the regulatory basis and
49 CFR (Transportation).
Check Digit Verification of cas no
The CAS Registry Mumber 7440-14-4 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,4,4 and 0 respectively; the second part has 2 digits, 1 and 4 respectively.
Calculate Digit Verification of CAS Registry Number 7440-14:
(6*7)+(5*4)+(4*4)+(3*0)+(2*1)+(1*4)=84
84 % 10 = 4
So 7440-14-4 is a valid CAS Registry Number.
InChI:InChI=1/Ra.2H/rH2Ra/h1H2
