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This article is about the chemical element. For other uses, seeRadium (disambiguation).
Not to be confused withRadon.

Radium,88Ra
Radium
Pronunciation/ˈreɪdiəm/​(RAY-dee-əm)
Appearancesilvery white metallic
Mass number[226]
Radium in theperiodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Ba
↑
Ra
↓
(Ubn)
francium←radium→actinium
Atomic number(Z)88
Groupgroup 2 (alkaline earth metals)
Periodperiod 7
Blocks-block
Electron configuration[Rn] 7s2
Electrons per shell2, 8, 18, 32, 18, 8, 2
Physical properties
PhaseatSTPsolid
Melting point973K​(700 °C, ​1292 °F)(disputed)
Boiling point2010 K ​(1737 °C, ​3159 °F)
Density(nearr.t.)5.5 g/cm3
Heat of fusion8.5kJ/mol
Heat of vaporization113 kJ/mol
Vapor pressure
P(Pa) 1 10 100 1 k 10 k 100 k
atT(K) 819 906 1037 1209 1446 1799
Atomic properties
Oxidation states+2(expected to have a stronglybasicoxide)
ElectronegativityPauling scale: 0.9
Ionization energies
  • 1st: 509.3 kJ/mol
  • 2nd: 979.0 kJ/mol
Covalent radius221±2pm
Van der Waals radius283 pm
Color lines in a spectral range
Spectral linesof radium
Other properties
Natural occurrencefrom decay
Crystal structure​body-centered cubic(bcc) (cF4)
Lattice constant
Body-centered cubic crystal structure for radium
a= 514.8 pm (nearr.t.)[1]
Thermal conductivity18.6 W/(m⋅K)
Electrical resistivity1 µΩ⋅m (at 20 °C)
Magnetic orderingnonmagnetic
CAS Number7440-14-4
History
DiscoveryPierreandMarie Curie(1898)
First isolationMarie Curie(1910)
Isotopes of radium
Main isotopes[2] Decay
abun­dance half-life(t1/2) mode pro­duct
223Ra trace 11.43 d α 219Rn
224Ra trace 3.6319 d α 220Rn
225Ra trace 14.9 d β− 225Ac
226Ra trace 1599 y α 222Rn
228Ra trace 5.75 y β− 228Ac
Category: Radium
|references
  • Radium-226 radiation source.
  • Activity 3300 Bq (3.3 kBq)

Radiumis achemical element;it hassymbolRaandatomic number88. It is the sixth element ingroup 2of theperiodic table,also known as thealkaline earth metals.Pure radium is silvery-white, but it readily reacts with nitrogen (rather than oxygen) upon exposure to air, forming a black surface layer ofradium nitride(Ra3N2). Allisotopesof radium areradioactive,the most stable isotope beingradium-226with ahalf-lifeof 1,600 years. When radium decays, it emitsionizing radiationas a by-product, which can excitefluorescentchemicals and causeradioluminescence.Of theradioactive elementsthat occur in quantity, radium is considered the mosttoxic.

Radium, in the form ofradium chloride,wasdiscoveredbyMarieandPierre Curiein 1898 from ore mined atJáchymov.They extracted the radium compound fromuraniniteand published the discovery at theFrench Academy of Sciencesfive days later. Radium was isolated in itsmetallicstate by Marie Curie andAndré-Louis Debiernethrough theelectrolysisof radium chloride in 1910, and soon afterwards the metal started being produced on larger scales inAustria,theUnited States,andBelgium.However, the amount of radium produced globally has always been small in comparison to other elements, and by the 2010s, annual production of radium, mainly via extraction fromspent nuclear fuel,was less than 100 grams.

In nature, radium is found inuraniumores in quantities as small as a seventh of a gram per ton of uraninite, and inthoriumores in trace amounts. Radium is not necessary forliving organisms,and its radioactivity and chemical reactivity make adverse health effects likely when it is incorporated into biochemical processes because of its chemical mimicry ofcalcium.As of 2018, other than innuclear medicine,radium has no commercial applications. Formerly, from the 1910s to the 1970s, it was used as a radioactive source forradioluminescentdevices and also inradioactive quackeryfor its supposed curative power. In nearly all of its applications, radium has been replaced with less dangerousradioisotopes,with one of its few remaining non-medical uses being the production ofactiniuminnuclear reactors.

Bulk properties

Radium is the heaviest knownalkaline earth metaland is the onlyradioactivemember of its group. Its physical and chemical properties most closely resemble its lightercongener,barium.[3]

Pure radium is avolatilesilvery-white metal, although its lighter congenerscalcium,strontium,and barium have a slight yellow tint.[3]This tint rapidly vanishes on exposure to air, yielding a black layer of what is probablyradium nitride(Ra3N2).[4]Itsmelting pointis either 700 °C (1,292 °F) or 960 °C (1,760 °F)[a]and itsboiling pointis 1,737 °C (3,159 °F); however, this is not well established.[5]Both of these values are slightly lower than those of barium, confirmingperiodic trendsdown the group 2 elements.[6] Like barium and thealkali metals,radium crystallizes in thebody-centered cubicstructure atstandard temperature and pressure:the radium–radium bond distance is 514.8picometers.[7] Radium has a density of 5.5 g/cm3,higher than that of barium, again confirming periodic trends; the radium-barium density ratio is comparable to the radium-barium atomic mass ratio,[8]due to the two elements' similar crystal structures.[8][9]

Isotopes

Main article:Isotopes of radium
Decay chainof238U, the primordialprogenitorof226Ra

Radium has 33 known isotopes withmass numbersfrom 202 to 234, all of which areradioactive.[2]Four of these –223Ra(half-life11.4 days),224Ra (3.64 days),226Ra (1600 years), and228Ra (5.75 years) – occur naturally in thedecay chainsof primordialthorium-232,uranium-235,anduranium-238(223Ra from uranium-235,226Ra from uranium-238, and the other two from thorium-232). These isotopes nevertheless still havehalf-livestoo short to beprimordial radionuclides,and only exist in nature from these decay chains.[10] Together with the mostlyartificial225Ra (15 d), which occurs in nature only as a decay product of minute traces ofneptunium-237,[11] these are the five most stable isotopes of radium.[2]All other 27 known radium isotopes have half-lives under two hours, and the majority have half-lives under a minute.[2]Of these,221Ra (half-life 28 s) also occurs as a237Np daughter, and220Ra and222Ra would be produced by the still-unobserveddouble beta decayof naturalradon isotopes.[12]At least 12nuclear isomershave been reported, the most stable of which is radium-205m with a half-life between 130~230 milliseconds; this is still shorter than twenty-fourground-stateradium isotopes.[2]

In the early history of the study of radioactivity, the different natural isotopes of radium were given different names, as it was not untilFrederick Soddy's scientific career in the early 1900s that the concept of isotopes was realized.[13]In this scheme,223Ra was named actinium X (AcX),224Ra thorium X (ThX),226Ra radium (Ra), and228Ra mesothorium 1 (MsTh1).[10]When it was realized that all of these are isotopes of the same element, many of these names fell out of use, and "radium" came to refer to all isotopes, not just226Ra,[14]though mesothorium 1 in particular was still used for some time, with a footnote explaining that it referred to228Ra.[15]Some of radium-226's decay products received historical names including "radium", ranging from radiumAto radiumG,with the letter indicating approximately how far they were down the chain from their parent226Ra:Radium emanation =222Rn,RaA=218Po,RaB=214Pb,RaC=214Bi,RaC1=214Po,RaC2=210Tl,RaD=210Pb,RaE=210Bi,RaF=210Po,andRaG=206Pb.[16]

226Ra is the most stable isotope of radium and is the last isotope in the(4n+ 2)decay chain of uranium-238 with a half-life of over a millennium; it makes up almost all of natural radium. Its immediate decay product is the dense radioactivenoble gasradon(specifically the isotope222Rn), which is responsible for much of the danger of environmental radium.[17][b]It is 2.7 million times more radioactive than the samemolar amountof naturaluranium(mostly uranium-238), due to its proportionally shorter half-life.[18][19]

A sample of radium metal maintains itself at a highertemperaturethan its surroundings because of the radiation it emits. Natural radium (which is mostly226Ra) emits mostlyalpha particles,but other steps in its decay chain (theuranium or radium series) emit alpha orbeta particles,and almost all particle emissions are accompanied bygamma rays.[20]

Experimental nuclear physics studies have shown that nuclei of several radium isotopes, such as222Ra,224Ra and226Ra, have reflection-asymmetric ( "pear-like" ) shapes.[21]In particular, this experimental information on radium-224 has been obtained atISOLDEusing a technique calledCoulomb excitation.[22][23]

Chemistry

Radium, like barium, is a highlyreactivemetal and always exhibits its group oxidation state of +2.[4]It forms the colorless Ra2+cationinaqueous solution,which is highlybasicand does not formcomplexesreadily.[4]Most radium compounds are therefore simpleioniccompounds,[4]though participation from the 6s and 6p electrons (in addition to the valence 7s electrons) is expected due torelativistic effectsand would enhance thecovalentcharacter of radium compounds such asRaF2and RaAt2.[24]For this reason, thestandard electrode potentialfor the half-reaction Ra2+(aq) + 2e-→ Ra (s) is −2.916V,even slightly lower than the value −2.92 V for barium, whereas the values had previously smoothly increased down the group (Ca: −2.84 V; Sr: −2.89 V; Ba: −2.92 V).[25]The values for barium and radium are almost exactly the same as those of the heavier alkali metalspotassium,rubidium,andcaesium.[25]

Compounds

Solid radium compounds are white as radium ions provide no specific coloring, but they gradually turn yellow and then dark over time due to self-radiolysisfrom radium'salpha decay.[4]Insoluble radium compoundscoprecipitatewith all barium, moststrontium,and mostleadcompounds.[26]

Radium oxide(RaO) has not been characterized well past its existence, despite oxides being common compounds for the other alkaline earth metals.Radium hydroxide(Ra(OH)2) is the most readily soluble among the alkaline earth hydroxides and is a stronger base than its barium congener,barium hydroxide.[27]It is also more soluble thanactinium hydroxideandthorium hydroxide:these three adjacent hydroxides may be separated by precipitating them withammonia.[27]

Radium chloride(RaCl2) is a colorless, luminous compound. It becomes yellow after some time due to self-damage by thealpha radiationgiven off by radium when it decays. Small amounts of barium impurities give the compound a rose color.[27]It is soluble in water, though less so thanbarium chloride,and its solubility decreases with increasing concentration ofhydrochloric acid.Crystallization from aqueous solution gives the dihydrate RaCl2·2H2O, isomorphous with its barium analog.[27]

Radium bromide(RaBr2) is also a colorless, luminous compound.[27]In water, it is more soluble than radium chloride. Like radium chloride, crystallization from aqueous solution gives the dihydrate RaBr2·2H2O, isomorphous with its barium analog. The ionizing radiation emitted by radium bromide excitesnitrogenmolecules in the air, making it glow. Thealpha particlesemitted by radium quickly gain two electrons to become neutralhelium,which builds up inside and weakens radium bromide crystals. This effect sometimes causes the crystals to break or even explode.[27]

Radium nitrate(Ra(NO3)2) is a white compound that can be made by dissolvingradium carbonateinnitric acid.As the concentration of nitric acid increases, the solubility of radium nitrate decreases, an important property for the chemical purification of radium.[27]

Radium forms much the same insoluble salts as its lighter congener barium: it forms the insolublesulfate(RaSO4,the most insoluble known sulfate),chromate(RaCrO4),carbonate(RaCO3),iodate(Ra(IO3)2),tetrafluoroberyllate(RaBeF4), and nitrate (Ra(NO3)2). With the exception of the carbonate, all of these are less soluble in water than the corresponding barium salts, but they are all isostructural to their barium counterparts. Additionally,radium phosphate,oxalate,andsulfiteare probably also insoluble, as theycoprecipitatewith the corresponding insoluble barium salts.[28]The great insolubility of radium sulfate (at 20 °C, only 2.1mgwill dissolve in 1kgof water) means that it is one of the less biologically dangerous radium compounds.[29]The large ionic radius of Ra2+(148 pm) results in weak complexation and poor extraction of radium from aqueous solutions when not at high pH.[30]

Occurrence

All isotopes of radium have half-lives much shorter than theage of the Earth,so that any primordial radium would have decayed long ago. Radium nevertheless still occursin the environment,as the isotopes223Ra,224Ra,226Ra, and228Ra are part of the decay chains of natural thorium and uranium isotopes; since thorium and uranium have very long half-lives, thesedaughtersare continually being regenerated by their decay.[10]Of these four isotopes, the longest-lived is226Ra (half-life 1600 years), a decay product of natural uranium. Because of its relative longevity,226Ra is the most common isotope of the element, making up about onepart per trillionof the Earth's crust; essentially all natural radium is226Ra.[31]Thus, radium is found in tiny quantities in the uranium oreuraniniteand various other uraniumminerals,and in even tinier quantities in thorium minerals. Onetonofpitchblendetypically yields about one seventh of agramof radium.[32]One kilogram of theEarth's crustcontains about 900picogramsof radium, and oneliterofsea watercontains about 89femtogramsof radium.[33]

History

Further information:Marie Curie § New elements
Marie and Pierre Curie experimenting with radium, a drawing byAndré Castaigne
Glass tube of radium chloride kept by the US Bureau of Standards that served as the primary standard of radioactivity for the United States in 1927.

Radium wasdiscoveredbyMarie Skłodowska-Curieand her husbandPierre Curieon 21 December 1898 in auraninite(pitchblende) sample fromJáchymov.[34]While studying the mineral earlier, the Curies removed uranium from it and found that the remaining material was still radioactive. In July 1898, while studying pitchblende, they isolated an element similar tobismuthwhich turned out to bepolonium.They then isolated a radioactive mixture consisting of two components: compounds ofbarium,which gave a brilliant green flame color, and unknown radioactive compounds which gavecarminespectral linesthat had never been documented before. The Curies found the radioactive compounds to be very similar to the barium compounds, except they were less soluble. This discovery made it possible for the Curies to isolate the radioactive compounds and discover a new element in them. The Curies announced their discovery to theFrench Academy of Scienceson 26 December 1898.[35]The naming of radium dates to about 1899, from the French wordradium,formed in Modern Latin fromradius(ray): this was in recognition of radium's emission of energy in the form of rays.[36]The gaseous emissions of radium, radon, were recognized and studied extensively byFriedrich Ernst Dornin the early 1900s, though at the time they were characterized as "radium emanations".[37]

In September 1910, Marie Curie andAndré-Louis Debierneannounced that they had isolated radium as a puremetalthrough theelectrolysisof pure radiumchloride(RaCl2) solution using amercurycathode,producing radium–mercuryamalgam.[38]This amalgam was then heated in an atmosphere ofhydrogengas to remove the mercury, leaving pure radium metal.[39] Later that same year, E. Eoler isolated radium bythermal decompositionof itsazide,Ra(N3)2.[10]Radium metal was first industrially produced at the beginning of the 20th century byBiraco,a subsidiary company ofUnion Minière du Haut Katanga(UMHK) in itsOlenplant in Belgium.[40]The metal became an important export of Belgium from 1922 up until World War II.[41]

The general historical unit for radioactivity, thecurie,is based on the radioactivity of226Ra. it was originally defined as the radioactivity of one gram of radium-226,[42]but the definition was later refined to be3.7×1010disintegrations per second.[43]

Historical applications

Luminescent paint

Radium watch hands under ultraviolet light

Radium was formerly used inself-luminouspaints for watches, nuclear panels, aircraft switches, clocks, and instrument dials. A typical self-luminous watch that uses radium paint contains around 1 microgram of radium.[44]In the mid-1920s, a lawsuit was filed against theUnited States Radium Corporationby five dying "Radium Girls"– dial painters who had painted radium-basedluminous painton the dials of watches and clocks. The dial painters were instructed to lick their brushes to give them a fine point, thereby ingesting radium.[45] Their exposure to radium caused serious health effects which included sores,anemia,andbone cancer.[17]

During the litigation, it was determined that the company's scientists and management had taken considerable precautions to protect themselves from the effects of radiation, but it did not seem to protect their employees. Additionally, for several years the companies had attempted to cover up the effects and avoid liability by insisting that the Radium Girls were instead suffering fromsyphilis.[46]

As a result of the lawsuit, and an extensive study by the U.S. Public Health Service, the adverse effects of radioactivity became widely known, and radium-dial painters were instructed in proper safety precautions and provided with protective gear. In particular, dial painters no longer licked paint brushes to shape them (which caused some ingestion of radium salts). Radium was still used in dials as late as the 1960s, but there were no further injuries to dial painters.[47]

From the 1960s the use of radium paint was discontinued. In many cases luminous dials were implemented with non-radioactive fluorescent materials excited by light; such devices glow in the dark after exposure to light, but the glow fades.[17]Where long-lasting self-luminosity in darkness was required, safer radioactivepromethium-147 (half-life 2.6 years) ortritium(half-life 12 years) paint was used; both continue to be used as of 2018.[48]These had the added advantage of not degrading the phosphor over time, unlike radium.[49]Tritium as it is used in these applications is considered safer than radium,[50]as it emits very low-energybeta radiation(even lower-energy than the beta radiation emitted by promethium)[51]which cannot penetrate the skin,[52]unlike the gamma radiation emitted by radium isotopes.[50]

A zeppelinaltimeterfromWorld War I.The dial, previously painted with a luminescent radium paint, has turned yellow due to the degradation of the fluorescentzinc sulfidemedium.

Clocks, watches, and instruments dating from the first half of the 20th century, often in military applications, may have been painted with radioactive luminous paint. They are usually no longer luminous; however, this is not due to radioactive decay of the radium (which has a half-life of 1600 years) but to the fluorescence of the zinc sulfide fluorescent medium being worn out by the radiation from the radium.[53] The appearance of an often thick layer of green or yellowish brown paint in devices from this period suggests a radioactive hazard. The radiation dose from an intact device is relatively low and usually not an acute risk; but the paint is dangerous if released and inhaled or ingested.[5][54]

Commercial use

Main articles:Radioactive quackeryandRadium fad

Radium was once an additive in products such as toothpaste, hair creams, and even food items due to its supposed curative powers.[55]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,RadithororRevigatortypes of "radium water" or "Standard Radium Solution for Drinking".)[53]Spasfeaturing radium-rich water are still occasionally touted as beneficial, such as those inMisasa, Tottori,Japan,[56]though the sources of radioactivity in these spas vary and may be attributed toradonand other radioisotopes.[57]In the U.S., nasal radium irradiation was also administered to children to prevent middle-ear problems or enlarged tonsils from the late 1940s through the early 1970s.[58]

Medical use

1918 ad for Radior cosmetics, which the manufacturer claimed contained radium.

Radium (usually in the form ofradium chlorideorradium bromide) was used inmedicineto produce radon gas, which in turn was used as acancertreatment; for example, several of these radon sources were used in Canada in the 1920s and 1930s.[5][59] However, many treatments that were used in the early 1900s are not used anymore because of the harmful effects radium bromide exposure caused. Some examples of these effects areanaemia,cancer, andgenetic mutations.[60]As of 2011, safer gamma emitters such as60Co,which is less costly and available in larger quantities, were usually used to replace the historical use of radium in this application,[30]but factors including increasing costs of cobalt and risks of keeping radioactive sources on site have led to an increase in the use oflinear particle acceleratorsfor the same applications.[61]

Early in the 1900s, biologists used radium to induce mutations and studygenetics.As early as 1904, Daniel MacDougal used radium in an attempt to determine whether it could provoke sudden large mutations and cause major evolutionary shifts.Thomas Hunt Morganused radium to induce changes resulting in white-eyed fruit flies. Nobel-winning biologistHermann Mullerbriefly studied the effects of radium on fruit fly mutations before turning to more affordable x-ray experiments.[62]

Howard Atwood Kelly,one of the founding physicians ofJohns Hopkins Hospital,was a major pioneer in the medical use of radium to treat cancer.[63] His first patient was his own aunt in 1904, who died shortly after surgery.[64] Kelly was known to use excessive amounts of radium to treat various cancers and tumors. As a result, some of his patients died from radium exposure.[65] His method of radium application was inserting a radium capsule near the affected area, then sewing the radium "points" directly to thetumor.[65]This was the same method used to treatHenrietta Lacks,the host of the originalHeLa cells,forcervical cancer.[66] As of 2015, safer and more available radioisotopes are used instead.[17]

Production

Monument to the Discovery of Radium inJáchymov

Uranium had no large scale application in the late 19th century and therefore no large uranium mines existed. In the beginning the only large source for uranium ore was thesilvermines inJáchymov,Austria-Hungary(nowCzech Republic).[34]The uranium ore was only abyproductof the mining activities.[67]

In the first extraction of radium, Curie used the residues after extraction of uranium from pitchblende. The uranium had been extracted by dissolution insulfuric acidleaving radium sulfate, which is similar tobarium sulfatebut even less soluble in the residues. The residues also contained rather substantial amounts of barium sulfate which thus acted as a carrier for the radium sulfate. The first steps of the radium extraction process involved boiling with sodium hydroxide, followed byhydrochloric acidtreatment to minimize impurities of other compounds. The remaining residue was then treated withsodium carbonateto convert the barium sulfate into barium carbonate (carrying the radium), thus making it soluble in hydrochloric acid. After dissolution, the barium and radium were reprecipitated as sulfates; this was then repeated to further purify the mixed sulfate. Some impurities that form insoluble sulfides were removed by treating the chloride solution withhydrogen sulfide,followed by filtering. When the mixed sulfates were pure enough, they were once more converted to mixed chlorides; barium and radium thereafter were separated byfractional crystallisationwhile monitoring the progress using aspectroscope(radium gives characteristic red lines in contrast to the green barium lines), and theelectroscope.[68]

After the isolation of radium by Marie and Pierre Curie from uranium ore fromJáchymov,several scientists started to isolate radium in small quantities. Later, small companies purchased mine tailings from Jáchymov mines and started isolating radium. In 1904, the Austrian governmentnationalisedthe mines and stopped exporting raw ore. Until 1912 when radium production increased, radium availability was low.[67]

The formation of an Austrian monopoly and the strong urge of other countries to have access to radium led to a worldwide search for uranium ores. The United States took over as leading producer in the early 1910s. Thecarnotitesands inColoradoprovide some of the element, but richer ores are found in theCongoand the area of theGreat Bear Lakeand theGreat Slave Lakeof northwestern Canada. Neither of the deposits is mined for radium but the uranium content makes mining profitable.[34][69]

The Curies' process was still used for industrial radium extraction in 1940, but mixed bromides were then used for the fractionation. If the barium content of the uranium ore is not high enough it is easy to add some to carry the radium. These processes were applied to high grade uranium ores but may not work well with low grade ores.[70]Small amounts of radium were still extracted from uranium ore by this method of mixed precipitation and ion exchange as late as the 1990s,[31]but as of 2011, it is extracted only from spent nuclear fuel.[71]

In 1954, the total worldwide supply of purified radium amounted to about 5 pounds (2.3 kg).[44]The chief radium-producing countries are Belgium, Canada, the Czech Republic, Slovakia, the United Kingdom, and Russia.[31]Zaireand Canada were briefly the largest producers of radium in the late 1970s.[72]The amounts of radium produced were and are always relatively small; for example, in 1918, 13.6 g of radium were produced in the United States,[73]and 70 g total were produced from 1913 to 1920 inPittsburgh.[72]The annual production of pure radium compounds was only about 100 g in total as of 1984;[31]annual production of radium had reduced to less than 100 g by 2018.[74]The metal is isolated by reducing radium oxide with aluminium metal in a vacuum at 1,200 °C.[30]

Modern applications

Radium is seeing increasing use in the field ofatomic, molecular, and optical physics.[75][23]Symmetry breaking forces scale proportional to[76]which makes radium, the heaviest alkaline earth element, well suited for constraining new physics beyond thestandard model.Some radium isotopes, such as radium-225, haveoctupoledeformed parity doublets that enhance sensitivity tocharge parity violatingnew physics by two to three orders of magnitude compared to199Hg.[77]

Radium is also a promising candidate for trapped ionoptical clocks.The radium ion has two subhertz-linewidth transitions from theground state that could serve as the clock transition in an optical clock.[78]A226Ra+ trapped ion atomic clock has been demonstrated on thetotransition, which has been considered for the creation of a transportable optical clock as all transitions necessary for clock operation can be addressed with direct diode lasers at common wavelengths.[79]

Some of the few practical uses of radium are derived from its radioactive properties. More recently discoveredradioisotopes,such ascobalt-60andcaesium-137,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.[80]

The isotope223Rawas approved by the United StatesFood and Drug Administrationin 2013 for use inmedicineas acancertreatment of bonemetastasisin the form of a solution including radium-223 chloride.[81]The main indication of treatment is the therapy ofbony metastasesfrom castration-resistant prostate cancer.[82] 225Ra has also been used in experiments concerning therapeutic irradiation, as it is the only reasonably long-lived radium isotope which does not have radon as one of its daughters.[83]

Radium was still used in 2007 as a radiation source in someindustrial radiographydevices to check for flawed metallic parts, similarly toX-ray imaging.[17]When mixed withberyllium,radium acts as aneutron source.[53][84]Up until at least 2004, radium-beryllium neutron sources were still sometimes used,[17][85] but other materials such aspoloniumandamericiumhave become more common for use in neutron sources. RaBeF4-based (α, n) neutron sources have been deprecated despite the high number of neutrons they emit (1.84×106neutrons per second) in favour of241Am–Be sources.[86]As of 2011,the isotope226Ra is mainly used to form227Acbyneutron irradiationin a nuclear reactor.[30]

Hazards

Radium is highly radioactive, as is its immediate decay product,radongas. When ingested, 80% of the ingested radium leaves the body through thefeces,while the other 20% goes into thebloodstream,mostly accumulating in the bones. This is because the body treats radium ascalciumanddeposits it in the bones,where radioactivity degradesmarrowand can mutatebone cells.Exposure to radium, internal or external, can cause cancer and other disorders, because radium and radon emit alpha andgamma raysupon their decay, which kill and mutate cells.[17]At the time of theManhattan Projectin the 1940s, the "tolerance level" for workers was set at 0.1 micrograms of ingested radium.[87]

Some of the biological effects of radium include the first case of "radium-dermatitis", reported in 1900, two years after the element's discovery. The French physicistAntoine Becquerelcarried a small ampoule of radium in his waistcoat pocket for six hours and reported that his skin becameulcerated.Pierre Curie attached a tube filled with radium to his arm for ten hours, which resulted in the appearance of a skin lesion, suggesting the use of radium to attack cancerous tissue as it had attacked healthy tissue.[88] Handling of radium has been blamed for Marie Curie's death, due toaplastic anemia.A significant amount of radium's danger comes from its daughter radon, which as a gas can enter the body far more readily than can its parent radium.[17]

As of 2015,226Ra is considered to be the most toxic of the quantity radioelements, and it must be handled in tightglove boxeswith significant airstream circulation that is then treated to avoid escape of its daughter222Rn to the environment. Old ampoules containing radium solutions must be opened with care because radiolytic decomposition of water can produce an overpressure of hydrogen and oxygen gas.[30] The world's largest concentration of226Ra is stored within theInterim Waste Containment Structure,approximately 9.6 mi (15.4 km) north ofNiagara Falls, New York.[89]

In the United States, theEnvironmental Protection Agency-defined Maximum Contaminant Level for radium is 5 pCi/L for drinking water;[90]theOccupational Safety and Health Administrationdoes not specifically set exposure limits for radium, and instead limits ionizing radiation exposure in units ofroentgen equivalent manbased on the exposed area of the body. Radioactive material exposure is regulated more closely by theNuclear Regulatory Commission,[91]which sets the exposure limit to226Ra at 0.01 μCi. Outside of the United States, exposure to radium is regulated by theInternational Commission on Radiological Protectionand theWorld Health Organization.[92]

Notes

  1. ^ Both values are encountered in sources and there is no agreement among scientists as to the true value of the melting point of radium.[4]
  2. ^Seeradon mitigation.

References

  1. ^Arblaster, John W. (2018).Selected Values of the Crystallographic Properties of Elements.Materials Park, Ohio: ASM International.ISBN978-1-62708-155-9.
  2. ^abcdeKondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021)."The NUBASE2020 evaluation of nuclear properties"(PDF).Chinese Physics C.45(3): 030001.doi:10.1088/1674-1137/abddae.
  3. ^abGreenwood & Earnshaw 1997,p. 112.
  4. ^abcdefKirby & Salutsky 1964,p. 4.
  5. ^abc "Radium".Encyclopædia Britannica.Archived fromthe originalon 15 June 2013.
  6. ^Lide, D.R.; et al., eds. (2004).CRC Handbook of Chemistry and Physics(84th ed.). Boca Raton, FL: CRC Press.ISBN978-0-8493-0484-2.
  7. ^Weigel, F.; Trinkl, A. (1968). "Zur Kristallchemie des Radiums" [On radium's chemical chrystalography].Radiochim. Acta(in German).10(1–2): 78.doi:10.1524/ract.1968.10.12.78.S2CID100313675.
  8. ^abYoung, David A. (1991)."Radium".Phase Diagrams of the Elements.University of California Press. p. 85.ISBN978-0-520-91148-2.
  9. ^"Crystal structures of the chemical elements at 1 bar".uni-bielefeld.de.Archived fromthe originalon 26 August 2014.
  10. ^abcdKirby & Salutsky 1964,p. 3.
  11. ^ Peppard, D.F.; Mason, G.W.; Gray, P.R.; Mech, J.F (1952)."Occurrence of the (4n+ 1) series in nature ".Journal of the American Chemical Society.74(23): 6081–6084.doi:10.1021/ja01143a074.Archivedfrom the original on 28 July 2019.Retrieved6 July2019.
  12. ^Tretyak, V.I.; Zdesenko, Yu.G. (2002). "Tables of Double Beta Decay Data — An Update".At. Data Nucl. Data Tables.80(1): 83–116.Bibcode:2002ADNDT..80...83T.doi:10.1006/adnd.2001.0873.
  13. ^Nagel, Miriam C. (September 1982)."Frederick Soddy: From alchemy to isotopes".Journal of Chemical Education.59(9): 739.Bibcode:1982JChEd..59..739N.doi:10.1021/ed059p739.ISSN0021-9584.
  14. ^Giunta, Carmen J. (2017)."ISOTOPES: IDENTIFYING THE BREAKTHROUGH PUBLICATION (1)"(PDF).Bull. Hist. Chem.42(2): 103–111.
  15. ^Looney, William B. (1958)."Effects of Radium in Man".Science.127(3299): 630–633.Bibcode:1958Sci...127..630L.doi:10.1126/science.127.3299.630.ISSN0036-8075.JSTOR1755774.PMID13529029.
  16. ^ Kuhn, W. (1929). "LXVIII. Scattering of thoriumC"γ-radiation by radiumGand ordinary lead ".The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science.8(52): 628.doi:10.1080/14786441108564923.ISSN1941-5982.
  17. ^abcdefgh Radiation protection.Radium.epa.gov(Report). Radiation / Radionuclides.United States Environmental Protection Agency.Archived fromthe originalon 11 February 2015.
  18. ^ Soddy, Frederick (25 August 2004).The Interpretation of Radium.Courier Corporation. p. 139 ff.ISBN978-0-486-43877-1.Archivedfrom the original on 5 September 2015.Retrieved27 June2015– via Google Books.
  19. ^ Malley, Marjorie C. (2011).Radioactivity.Oxford University Press. p.115 ff.ISBN978-0-19-983178-4.Retrieved27 June2015– via Internet Archive (archive.org).
  20. ^Strutt, R.J. (7 September 2004).The Becquerel Rays and the Properties of Radium.Courier Corporation. p. 133.ISBN978-0-486-43875-7.Archivedfrom the original on 5 September 2015.Retrieved27 June2015.
  21. ^Butler, P. A. (2020)."Pear-shaped atomic nuclei".Proceedings of the Royal Society A.476(2239): 20200202.Bibcode:2020RSPSA.47600202B.doi:10.1098/rspa.2020.0202.PMC7426035.PMID32821242..
  22. ^"First observations of short-lived pear-shaped atomic nuclei – CERN".home.cern.Archivedfrom the original on 12 June 2018.Retrieved8 June2018.
  23. ^abGaffney, L. P.; Butler, P. A.; Scheck, M.; et al. (2013)."Studies of pear-shaped nuclei using accelerated radioactive beams".Nature.497(7448): 199–204.Bibcode:2013Natur.497..199G.doi:10.1038/nature12073.PMID23657348.S2CID4380776.
  24. ^Thayer, John S. (2010). "Relativistic Effects and the Chemistry of the Heavier Main Group Elements".Relativistic Methods for Chemists.Challenges and Advances in Computational Chemistry and Physics. Vol. 10. Dordrecht: Springer. p. 81.doi:10.1007/978-1-4020-9975-5_2.ISBN978-1-4020-9974-8.
  25. ^abGreenwood & Earnshaw 1997,p. 111.
  26. ^Kirby & Salutsky 1964,p. 8.
  27. ^abcdefgKirby & Salutsky 1964,pp. 4–8.
  28. ^Kirby & Salutsky 1964,pp. 8–9.
  29. ^Kirby & Salutsky 1964,p. 12.
  30. ^abcdeKeller, Wolf & Shani 2011,pp. 97–98.
  31. ^abcdGreenwood & Earnshaw 1997,pp. 109–110.
  32. ^"Radium"Archived15 November 2012 at theWayback Machine,Los Alamos National Laboratory. Retrieved 5 August 2009.
  33. ^Section 14, Geophysics, Astronomy, and Acoustics; Abundance of Elements in the Earth's Crust and in the Sea, in Lide, David R. (ed.),CRC Handbook of Chemistry and Physics,85th Edition.CRC Press. Boca Raton, Florida (2005).
  34. ^abcHammond, C. R. "Radium" inHaynes, William M., ed. (2011).CRC Handbook of Chemistry and Physics(92nd ed.). Boca Raton, FL:CRC Press.ISBN1-4398-5511-0.
  35. ^
  36. ^
  37. ^Stwertka, Albert (1998).A Guide to the Elements(revised ed.). Oxford University Press. p. 194.ISBN978-0-19-508083-4.
  38. ^Frank Moore Colby; Allen Leon Churchill (1911).New International Yearbook: A Compendium of the World's Progress.Dodd, Mead and Co. p.152 ff.
  39. ^ Curie, Marie & Debierne, André (1910)."Sur le radium métallique"[On metallic radium].Comptes Rendus(in French).151:523–525.Archivedfrom the original on 20 July 2011.Retrieved1 August2009.
  40. ^Ronneau, C.; Bitchaeva, O. (1997).Biotechnology for waste management and site restoration: Technological, educational, business, political aspects.Scientific Affairs Division, North Atlantic Treaty Organization. p. 206.ISBN978-0-7923-4769-9.Archivedfrom the original on 5 September 2015.Retrieved27 June2015.
  41. ^Adams, A (January 1993)."The origin and early development of the Belgian radium industry".Environment International.19(5): 491–501.doi:10.1016/0160-4120(93)90274-l.ISSN0160-4120.
  42. ^ Frame, Paul W. (October–November 1996)."How the Curie came to be".Health Physics Society Newsletter.Archived from the original on 20 March 2012.Retrieved9 May2023– viaOak Ridge Associated Universities(orau.org).{{cite magazine}}:CS1 maint: unfit URL (link)
  43. ^National Research Council (US) Committee on Evaluation of EPA Guidelines for Exposure to Naturally Occurring Radioactive Materials (1999). "Appendix, Radiation Quantities and Units, Definitions, Acronyms".Evaluation of Guidelines for Exposures to Technologically Enhanced Naturally Occurring Radioactive Materials.Washington (DC): National Academies Press (US).
  44. ^ab Terrill, J.G. Jr.; Ingraham, S.C., 2nd; Moeller, D.W. (1954)."Radium in the healing arts and in industry: Radiation exposure in the United States".Public Health Reports.69(3): 255–262.doi:10.2307/4588736.JSTOR4588736.PMC2024184.PMID13134440.{{cite journal}}:CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
  45. ^ Frame, Paul (1999)."Radioluminescent paint".Museum of Radiation and Radioactivity.Oak Ridge Associated Universities.Archivedfrom the original on 31 July 2014.
  46. ^"Environmental history timeline – Radium Girls".20 July 2012.Archivedfrom the original on 2 September 2018.Retrieved1 September2018.
  47. ^
  48. ^
  49. ^Lavrukhina, Avgusta Konstantinovna; Pozdnyakov, Aleksandr Aleksandrovich (1966).Аналитическая химия технеция, прометия, астатина и франция[Analytical Chemistry of Technetium, Promethium, Astatine, and Francium] (in Russian).Nauka.p. 118.
  50. ^abZerriffi, Hisham (January 1996)."Tritium: The environmental, health, budgetary, and strategic effects of the Department of Energy's decision to produce tritium".Institute for Energy and Environmental Research.Archivedfrom the original on 13 July 2010.Retrieved15 September2010.
  51. ^Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017)."The NUBASE2016 evaluation of nuclear properties"(PDF).Chinese Physics C.41(3): 030001.Bibcode:2017ChPhC..41c0001A.doi:10.1088/1674-1137/41/3/030001.
  52. ^ Hydrogen-3(PDF)(Report). Nuclide safety data sheet. Environmental Health & Safety Office,Emory University.Archived fromthe original(PDF)on 20 May 2013 – via ehso.emory.edu.
  53. ^abcEmsley 2003,p. 351.
  54. ^ "Luminous radium paint".vintagewatchstraps.com.Archived fromthe originalon 4 March 2013.
  55. ^"French Web site featuring products (medicines, mineral water, even underwear) containing radium".Archivedfrom the original on 15 March 2011.Retrieved1 August2009.
  56. ^Morinaga, H.; Mifune, M.; Furuno, K. (1984)."Radioactivity of water and air in Misasa Spa, Japan".Radiation Protection Dosimetry.7(1–4): 295–297.doi:10.1093/oxfordjournals.rpd.a083014.ISSN0144-8420– via International Nuclear Information System.
  57. ^
  58. ^ Cherbonnier, Alice (1 October 1997)."Nasal radium irradiation of children has health fallout".Baltimore Chronicle.Archivedfrom the original on 28 September 2011.Retrieved1 August2009.
  59. ^ Hayter, Charles (2005)."The politics of radon therapy in the 1930s".An Element of Hope: Radium and the response to cancer in Canada, 1900–1940.McGill-Queen's Press.ISBN978-0-7735-2869-7– via Google Books.
  60. ^Harvie, David I. (1999). "The radium century".Endeavour.23(3): 100–105.doi:10.1016/S0160-9327(99)01201-6.PMID10589294.
  61. ^Van Dyk, J.; Battista, J. J.; Almond, P. R. (2020)."A RETROSPECTIVE OF COBALT-60 RADIATION THERAPY:" THE ATOM BOMB THAT SAVES LIVES ""(PDF).Medical Physics International.
  62. ^Hamilton, Vivien (2016)."The Secrets of Life: Historian Luis Campos resurrects radium's role in early genetics research".Distillations.2(2): 44–45.Archivedfrom the original on 23 March 2018.Retrieved22 March2018.
  63. ^ "The Four Founding Physicians".About / History.Hopkins Medicine (hopkinsmedicine.org).Johns Hopkins School of Medicine,Johns Hopkins University.Archivedfrom the original on 10 March 2015.Retrieved10 April2013.
  64. ^ Dastur, Adi E.; Tank, P.D. (2011)."Howard Atwood Kelly: Much beyond the stitch".The Journal of Obstetrics and Gynecology of India.60(5): 392–394.doi:10.1007/s13224-010-0064-6.PMC3394615.
  65. ^ab Aronowitz, Jesse N.; Robison, Roger F. (2010). "Howard Kelly establishes gynecologic brachytherapy in the United States".Brachytherapy.9(2): 178–184.doi:10.1016/j.brachy.2009.10.001.PMID20022564.
  66. ^ Skloot, Rebecca (2 February 2010).The Immortal Life of Henrietta Lacks.Random House Digital.ISBN978-0-307-58938-5.Archivedfrom the original on 17 June 2013.Retrieved8 April2013.
  67. ^abCeranski, Beate (2008)."Tauschwirtschaft, Reputationsökonomie, Bürokratie".NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin(in German).16(4): 413–443.doi:10.1007/s00048-008-0308-z.
  68. ^"Lateral Science"Archived2 April 2015 at theWayback Machine.lateralscience.blogspot.se.November 2012
  69. ^Just, Evan; Swain, Philip W. & Kerr, William A. (1952). "Peacetíme Impact of Atomíc Energy".Financial Analysts Journal.8(1): 85–93.doi:10.2469/faj.v8.n1.85.JSTOR40796935.
  70. ^Kuebel, A. (1940). "Extraction of radium from Canadian pitchblende".Journal of Chemical Education.17(9): 417.Bibcode:1940JChEd..17..417K.doi:10.1021/ed017p417.
  71. ^Emsley 2003,p. 437.
  72. ^ab"Production, Import, Use and Disposal".Toxicological Profile for Radium.Atlanta (GA): Agency for Toxic Substances and Disease Registry (US). 4 December 1990.
  73. ^Viol, C.H. (1919)."Radium Production".Science.49(1262): 227–228.Bibcode:1919Sci....49..227V.doi:10.1126/science.49.1262.227.PMID17809659.
  74. ^Cantrill, Vikki (20 July 2018)."The realities of radium".Nature Chemistry.10(8): 898.doi:10.1038/s41557-018-0114-8.ISSN1755-4330.
  75. ^
  76. ^
  77. ^
  78. ^Nuñez Portela, M.; Dijck, E.A.; Mohanty, A.; Bekker, H.; van den Berg, J.E.; Giri, G.S.; et al. (1 January 2014). "Ra+ ion trapping: toward an atomic parity violation measurement and an optical clock".Applied Physics B.114(1): 173–182.Bibcode:2014ApPhB.114..173N.doi:10.1007/s00340-013-5603-2.S2CID119948902– via Springer Link.
  79. ^Holliman, C.A.; Fan, M.; Contractor, A.; Brewer, S.M.; Jayich, A.M. (20 January 2022)."Radium ion optical clock".Physical Review Letters.128(3): 033202.arXiv:2201.07330.Bibcode:2022PhRvL.128c3202H.doi:10.1103/PhysRevLett.128.033202.PMID35119894.S2CID246035333– via APS.
  80. ^
  81. ^
  82. ^ Maffioli, L.; Florimonte, L.; Costa, D.C.; Correia Castanheira, J.; Grana, C.; Luster, M.; et al. (2015)."New radiopharmaceutical agents for the treatment of castration-resistant prostate cancer".Q J Nucl Med Mol Imaging.59(4): 420–438.PMID26222274.
  83. ^Stoll, Wolfgang (2005). "Thorium and Thorium Compounds".Ullmann's Encyclopedia of Industrial Chemistry.Wiley-VCH.p. 717.doi:10.1002/14356007.a27_001.ISBN978-3-527-31097-5.
  84. ^l'Annunziata, Michael F. (2007)."Alpha particle induced nuclear reactions".Radioactivity: Introduction and history.Elsevier. pp. 260–261.ISBN978-0-444-52715-8.
  85. ^ Holden, N.E.; Reciniello, R.N.; Hu, J.P.; Rorer, David C. (2004)."Radiation dosimetry of a graphite moderated radium-beryllium source"(PDF).Health Physics.86(5 Supplement): S110–S112.Bibcode:2003rdtc.conf..484H.doi:10.1142/9789812705563_0060.PMID15069300.Archived(PDF)from the original on 23 July 2018.Retrieved25 October2017.
  86. ^Keller, Wolf & Shani 2011,pp. 96–98.
  87. ^
  88. ^ Redniss, Lauren (2011).Radioactive: Marie & Pierre Curie: A tale of love and fallout.New York, NY: HarperCollins. p. 70.ISBN978-0-06-135132-7.
  89. ^Jenks, Andrew (July 2002)."Model City USA: The Environmental Cost of Victory in World War II and the Cold War".Environmental History.12(77): 552–577.doi:10.1093/envhis/12.3.552.(subscription required)
  90. ^ EPA Facts about Radium(PDF).semspub.epa.gov(Report). U.S.Environmental Protection Agency.Retrieved6 March2023.
  91. ^"Ionizing Radiation".Occupational Safety and Health Administration.Retrieved13 August2024.
  92. ^"7. Regulations and Advisories".Toxicological Profile for Radium.Atlanta (GA): Agency for Toxic Substances and Disease Registry (US). 7 December 1990.

Bibliography

Further reading

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