.?w4*

National

Academy“V

of

Sciences

NationalResearchCouncil

H

N?C”LEARSCIENCESERIES

TheRadiochemistry

ofPolonium

COMMITTEEONNUCLEARSCIENCE

L.F.CURTIS,Chairm#!ROBLEYD.EVANS,ViceShairman

Natlon^ilureauDfStandardsMamachuaettffinetltut^?echnology

J.A.DeJUREN,Secre@ry

Weatinghou^ectrltorporation

C.J.BORKOWSKIJ.W.工RVfNEQR.

OakRidg^JationaUaboratoryMassachusettoBtituteofTechnology

ROBERTG.COCHRANE.D.IUEMA

TexasAgricultuiaa±iMechanicalNorthwestettaiiversity,

College

W.WAYNEMEINKE

SAMUELEPSTELNUniversib^Michigan

CalifornlaatItu±^?mhnologYJ.J.NICKSON

MemoriaJHoepitaflJ^wYork

U,FANO

Nation^hareauofStandardsROBERTL.PLATZMAN

LabomitoirieChimiePhysique

HERBERTGOLDSTEIN

NucleaDevelopmen(EorpratloKDfD.M.VANPATTER

AmericaBartoResesrclFoundation

LIAISONMEMBERS

PAULC.AEBERSOLDCHARLESK.REED

AtomicEnergyCommissionU.S:AirForce

j.HOWARDMCMILLENWILLIAME.WRIGHT

Nation^ciencFoundationOfficefNavslResearch

SUBCOhAMITTEEONRADIOCHEMISTRY

W.WAYNEMEINKE,ChairmanHAROLDKfRBY

UniversiofMichlgsn!MoundLaboratory

GREGORYR.CHOPPIN!GEORGELEDDICOTTE

FloridStat^niverai@?OakRidg^Jationd2aboratory

GEORGEA.COWAN;JULIANNIELSEN

LosAlamosScientiiiHtooratoryHanfomLaboratories

ARTHURW.FAKRHALLELLISP.STEINBERG

Unlversi@)fWashingtonArgonn^IationdJaboratory

JEROMEHUDISPETERC.STEVENSON

BrookhaveMationdJaboratoryUniveralt)$Californi^ivermore)

EARLHYDELEOYAFFE

Universl6>fCaliforniBerkeley)McGilIJnlversl@

CONSULTANTS

NATHANBALLOUJAMESDeVOE

NavalRadiologi<EBelfens^aboratoryUniversibfMlohigsn

WILLIAMMARLOW

Nation^ureainfStandamis

CHEMISTRY

TheRadiochemistryofPolonium

P.E.FIGGINS

Mound

Laboratory

MiamisbwgtOhio

Janum-yL961

SubcommitteeonRadiochemistry

NationaJAcademyofSciences-NationalResearchCouncil

PrintedUSA.Pric^O.70\.vallnkfLiBDirth^)ffico^Technical

Bervic^Sepwtme.ofCommerce^ashi@on25J).C.

FOREWORD

TheSubcommitteeonRadlocheml6tryIsoneofanumberof

subcommitteesworkingundertheCommitteeonNuclearScience

withintheNationalAcademyofSciences-NationalResearch

council-Itsmembersrepresentgovernment,industrial,and

universitylaboratoriesintheareasofnuclearchemistryand

analyticalchemistry.

The''SubcommitteehasconcernedItselfwiththoseareasof

nuclearsciencewhichtivolve,thechemist,suchasthecollec-

tionanddistributionofradiochemicalprocedures,theestab-

lishmentofspecifletitionsforradlochemicallypurereagents,

availabilityofcyclotrontimeforserviceirradiations,the

placeofradiochemistryIntheundergraduatecollegeprogram,

etc.

Thisseriesofmonographshasgrownoutoftheneedfor

up-to-datecompilationsofradiochemicalinformationandpro-

cedures.TheSubcommitteehasendeavoredtopresentaseries

whichwillbeofmsximumusetotheworkingscientistand

whichcontainsthelatestavailableinformation.Eachmono-

graphcollectsinonevolumethepertinentinformationrequired

forradiochemicalworkwithanindividualelementoragroupof

closelyrelatedelements.

Anexpertintheradiochemistryoftheparticularelement

haswrittenthemonograph,followingastsndardformatdeveloped

bytheSubcommittee.TheAtomicEnergyCommissionhassponsored

theprintingoftheseries.

TheSubcommitteeisconfidentthesepublicationswillbe

usefulnotonlytotheradiochemistbutalsototheresearch

workerInotherfieldssuchasphysics,biochemistryorzzmedlclne

whowishestouseradiochemicaltechniquestosolveaspecific

problem.

W.WayneMelnke,Chairman

SubcommitteeonRadiochemistry

ili

INTRODUCTION

Thisvolumewhichdealswiththeradiochemistryofpolonium

isoneofaseriesofmonographsonradiochemistryoftheelements.

ThereIsincluded,areviewofthenuclearandchemicalfeatures

ofparticularinteresttotheradlochemist,adiscussionofprob-

lemsofdissolutionofa.aampleandcountingtechniques,and

finally,acollectionofradiochemicalproceduresfortheelement

asfoundintheliterature.

Theseriesofmonographswillcoverallelementsforwhich”

radiochemicalproceduresarepertinent.Plansincluderevision

ofthemonographperiodicallyasnewtechniquesandprocedures

warrant.ThereaderIsthereforeencouragedtocalltothe

attentionoftheauthoranypublishedorunpublishedmaterialon

theradiochemistryofpoloniumwhichmightbeIncludedInarevised

versionofthemonograph.

iv

CONTENTS

I.GENEWLREVIEWSOFTilECHEMISTRYANDM+IO-

CHEMISTRYOFPOLONIUM..........................1

11.TABLEOFISOTOPES..................................3

III.REVIEWOFTHOSEFEATURESOFPOLONIUMCHEMISTRYOF

CHIEFINTERESTTOTHERADIOCHEMIST..........5

1.General5

2.MetallicPolonium7

3.OxidationStates9

4.SolubleSalts12

5.InsolubleCompoundsofPoloniumand

CoprecipitationBehavior16

6.Complex'工。ns20

7.SolventExtraction22

8.IonExchangeandPaperChromatography25

9.SublimationTechniques27

10.SpontaneousDepositionandElectrodeposition29

IV.DISSOLUTIONOFSAMPLES.............................34

v.COUNTINGTECHNIQUES................................35

VI.COLLECTIONOFDETAILEDRADIOCHEMICALPROCEDURES

FORPOLONIUM........................................36

v

TheRadiochemistryofPolonium

P.E.FIGGINS

Moundlaboratory*

Miamisburg,

Ohio

I.GENERALREVIEWSOFTHECHEMISTRYANDRADIOCHEMISTRYOF

POLONIUM

(1)llchmist^oftheRareRadioelements"byK.W.Bagnalls

pp.1-94,AcademicPressInc.,NewYork,1957,348refer-

ences(ThiscomprehensivereviewcoverstheliteratureUp

to1956.Sincealiteraturesearchoftheearlyworkon

Powouldonlyduplicatematerialpublishedinthisbock,

extensiveusehasbeen'made'ofthematerialcitedinthis

review.Theauthorwishestoac?ledgehisindebtedness

tothissource.)

(2)''Poloniummed.byH.V.Moyer,U?S.AtomicEnergyCommis-

sionTID-5221-381pp.1956(Asummaryoftheworkon

PeperformedatMoundLaboratory)

(3)Gme1inHandbuchderanorganischenChemie,SystemNumber

12,VerlagChemietG.m.b.H.,Berlin,1941(Acomprehen-

sivereviewoftheearlyPowerk.)

*OperatedbyMonsantoResearchCorporation,Mi?isburg,Ohio.

1

(4)'~LePoloniumzAct.Sci.517〃byM?Haissinsky,Herma?

etCie.tParis,1937

⑸1IElectrOchimietiesSubstancesradio-actives.Act.SCI.1009〃

byM.Haissinsky,Hermann一tCie.,Paris,1946

(6)Ifs?AspectsofPoloniumChemistry'ibyK.W.Bagnall,

Proc.Int.Conf.zGeneva,1955,z,pp.386-388,U.N.,

NewYork,1956.29references.

(7)''ChemistryofPolonium〃byK.W.Bagnall,Quart.Rev.,1.1,

30-48,(1957).79references.

(8)''ChemLedesPoloniums'IbyF,Weigel,Angew.Chemie,?，

289-299,1959.144references.

2

II.TABLEOFISOTOPES

Energyof

Radiations

IsotoDeHalf-LifqDecav(Mev.)MethodofPreparation

P01961.9ma6.14

pol974ma6.040

P01986ma5.935

pol99nma5.846

P0200I】mEC

a5.770

P020118mE.C

a5.671

PM51m98$ECDaughterofRn206

2$a5.575

po20342mEC

?02043.8h99$ECDaughterofRn208

1$a5.370DaughterofAt204

?0205

1.8h99+$EcDaughterofAt205

074%a5.2

Pb204(a,Jn)

P02G695$EcDaughterofRn2Lo

8.8d5$a

y5218DaughterofAt206

po2075.7h99+%ECPb206(a,3n)

~o-2$''5.10

Y

P02082.897y=a5.108Pb207(a,3n)

ECBi209(P,2n)

YBi209(,d,2n)

「K.C.Jordan,Privateccmmmnication.

3

Etirgyof

Radiations

IsotopeHalf-Life—(Mev.)Methodof:Prenarat~on

Bi209(p,n)

po209103y99+$a4.877Bi209(d,2n)

0.5%ECDaughterofAt209

Y

po210

138.401d99+$5.305Bi209(n,y)Bi210&-PO210

(RaF)10-3%a4.5DaughterofBi2~O(RaE)

po211m25sa7.14

7.85

8.7o

po211

0.52Ba7.ti2DaughterofB1211

(AcC‘)

po212

3X10-7sa8.780DaughterofBi212

(ThC，)

po2134.2x10-6sa8.35DaughterofBi213

DaughterofRn217

po2141.64x10-4sa7.68oDaughterofB1214

(Rae，)

P0215

1.83x10-3Sa7.36DaughterofRn219

(Au)DaughterofB1215

po216

0.158sa6.775DaughterofRn220

(ThA)

P0217

108a6.54DaughterofRn221

po218

3.05ma5998DaughterofRn222

(m)

Formorecompleteinformationontheradiationsof

thepoloniumisotopesandforreferencestoorigiml

literature,see''TableofIsotopesz1,D.Strominger,J.M.

HollanderandG.T.Seaborg,ReviewsofModernPhysics,

?,No.2,PartIIZApril1958.

4

Ill.REVIEWOFTHOSEFEATZLiREOFCHEMISTRYOFCHIEF

INTERESTTOTHEPOLONIUMBIOCHEMIST

1.General

PoloniumwasdiscoveredbyPierreandMarieCuriein1898in

thecourseofresearchontheradioactivityofuraniumandthorium

minerals.TheyfoundthatPobehavedsimilarlytoBiandsub-

sequentlywereabletoseparateitfromBibyvacuumsublimation.

TheearliestworkonPowascomplicatedbytheextremelysmall

quantitiesavailableandsometimesbyincompleteseparationof

radioactiveimpurities,sothatitwasnotuntil1906thatthe

identificationofPowasdefinitelyestablished.Until1944,

withoneexceptionl-,alloftheworkonPowasconductedontk

tracelevel.Whilemostoftheresultswerevalid,afew”

erroneousconclusionswerereachedconcerningthebasicthem-=

istryofPO,However,work

withmilligramquantitiesofPoduringthelast15yearshas

placedthechemistryofPoonasoundbasis.

Polonium-210(RaF)occursnaturallyintheuranium-radiumdecay

chain.TheequilibriumratioofUtoPois1.19x101'0,sothat

thePoconcentrationinuraniumoresislessthan0.1mg/ton.

.Theleadfractionofresiduesfromuraniumprocessing(RaDEF)

offersamoreconcentratedsourceofPo210,buttheconcen-

trationofPoisstilllessthanonemg/ton.Polonium-210

''canalsobeobtainedfromagedRasalts(0.2mgofPopergmof

Raatequilibrium)andfromagedRntubes.Withtheadventof

nuclearreactorsandtheirintenseneutronfluxes,thereaction

5

~3Bf209(n,y)83B工210j&#Po210hasbecomeeconomically

feasible.Thisprocessiscurrentlyusedfortheproduction

ofmilligramquantitiesofPO.

AnumberofotherisotopesofPoalsoappearinnaturaloccurring

decayseries.However,theshorthalf-livesofall,zpreclude

anyappreciableconcentrationoftheseIsotopesinnature.

Polonium-213isamemberoftheartificiallyproduced4n+l

series,butitshalf-lifeisalsoshort.

OneofthedifficultiesofworkingwithPo210isitshigh

specificactivity(0.2222mg/c).Theintenseradiationof

milligramsamplesquickl?decomposesmostorganiccompleting

agentsandeventhesolvents.Crystalstructuresofsolidsare

quicklydestroyedoraltered.Forthisreasonitwouldbedesir-

abletoworkwithanisotopeoflowerspecificactivity.The

useofP0209,withahalf-lifeof103yr.,wouldreduce

radiationeffectsabout600-fold.P010rIiUm209canbeformed

bybombardingBi209withprotonsinacyclotron?however,much

morePoz08(tl/2=3yr)isproducedthanPo209.Asample

ofPo208-Po209waspreparedbyOakRidgeNatiofialLaboratory

andpurifiedatMoundLaboratory.3Z4Thetotalssmplecontained

aboutonecurieofactivityariditwasestimatedthatthesample

containedL4.5XbyweightofPo209relativetothetotal

Pocontent.3Thissamplewasusedforspectroscopicmeasure-

ments4anddeterminationofthegammaspectrumofPo209.3〃

ThehandlingofPorequiresspecialprecautions.Sincethe

maximumpermissiblebodyburdenforingestedPoisonly0.02wc

6

(4.5X10-12gofPo210)safetyprecautionsmustbevigorously

Obsemed.Lwlevelsources,oftheorderofafewmillicuries,

canbehandledassolutionswithreasoriablesafetyinfumehoods

underanadequatedraft,butitisinadvisabletohandledry

sources,evenatthemillicurielevel,inanythingbutsealed

systems.DuetothevolatilityofsomePocompounds(e.g.

halides)andthehighspecificactivity,agloveboxsystemisrec-

comnendedforwcamountsandover.Foramoredetaileddiscussion

oftheproblemsassociatedwithhigh.levelsofPoseeReference

5,pp.32-42.

2.MetallicPolonium

Poloniummetalissilverygrayincolor,andissoftenough

tobescratchedreadily.Themetalreactsslowlywith

atroomtemperature,butrapidlyatelevatedtemperatures.

Therefore,thepuremetalshouldbestoredundervacuumorin

aninertatmosphere.Theintenseradiati~ofcurielevel

stiplescausesafluorescenceinthesurroundinggasandin

glassorsilicacontainers.Inthedark,aquitespectacular

blue-whiteglowisobsemedfromcurielevelmetallicsamples

orsuspensionsofinsolublePocompounds.Theintenseradiation

oflargesamplesofPohasaheatingeffect(27.4cal/hr/curie-

theoreticalvalue),5sothatthetemperatureofthesamplec-

bewellaboveitssurroundings.Theradiationalsoaffects

glassorsilicacontainers,causingthemtobecomedarkand

fragile(crazing).

EarlymeasurementsofthephysicalpropertiesofPowerehampered

7

bythesmallquantitiesofmaterialavailableandbyimpurity

ofthesamples.TableIlistssomeofthephysicalproperties

determinedatMoundLaboratorywithmilligramlevelsamples.

X-raypowderphotographyindicatesthatthemetalexistsinat

leasttwoallotropicmodifications:alowtemperatureaphase

withasimplecubiclatticeandahightemperaturePphase,

withasimplerhombohedrallattice.Thephasechangeoccurs

atabout360c,butthetwophasesmayco-existbetween18and

5b℃.7Becauseofthebestingeffectofthealpharadiations,

freshlypreparedPometalexistsinthePphase.AsthePo

decays,theheatingeffectdecreases,andtliemetalslowly

convertstotheaform.

TABLE1

PHYSICALPROPERTIESOFPOLONIUMMETAL*

DensLtyWt.-Vol.detn.9.3g/cm3(Sphase)

X-raya9.196g/cm3

P9.398g/cm3

MeltingPoint252*20C

BoilingPoint962.04?1.930C

(extrapolatedfromvaporpressuredata)

Heat''ofVaporization24,597z31cal/wle

「Reference6,pp.21-26

Thevaporpressureinthetemperaturerangeof438to745℃has

beenmeasured,8andthederivedvaporpreseureequationis

logP=-53772+6-7+7.2345-0.0068

T

whereTisthetemperaturein'KandPisthepressureinmn

8

m.Thisequationwasthenusedtocalculatetheboiling

pointofPo.

Thepuremetalcanbepreparedinanumberofways.'Theearli-

estattemptsinvolvingsublimationinairyielded-theoxide.

However,sublimationinaninertatmosphere(H2orN2)or

vacuumsublimationontoquartzorglassproducesthepure

metal.Platinumandpalladiumaswellasanumberofother

metalshavebeenusedtocondensePobutpolonideformation

mayoccurinsomecases.Themetalhasalsobeenpreparedin

，，

milligramamountsbycathodicdepositiononplatinumorgold.

Spontaneousdepositiononaleasnoblemetalyie-deametallic

deposit,butoftenthisiscontaminatedwithBi(,RaE).

Probablythesimplestmethodofobtainingmilligramquantities

ofpurepoloniumistoprecipitatethesulfidefrmndiluteHCL.

Uhentheprecipitateisheatedto500℃undervacuum,thesulfide

decomposesandpurePometalsublimes.9Z10ProcedureXIIdescribes

thismethodindetail.

3.OxidationStates

TheelectronconfigurationofneutralPoatomsinz,groundstates

isprobably5s25P65d莒#6p4(3P2)analogoustotheconfigur-

ationsofSeandTe,Eromwhichstableoxidationstatesof-2,

+2,+4,and+6wouldbeexpected.

PolonidesTheexistenceof.a-2oxidationstatewasfirst

suggestedbytheobse?wationthatwhenPowasmeltedwithAg

orCuzthePocouldnotberecoveredquantitativelybydistil-

9

lation.IfthePowaselectroplatedorvolatilizedontothese

metals,nosuchdifficultywasobsened.Recently,anumberof

polonideshavebeenpreparedonthemilligramscaleandcharac-

terized.Polonidesof.ZnzPb,Pt,Ni,Ag,Be,Ca,Na,Hg,and

Mghavebeenreported.5ZZz6TheelectrodepotentialforPo/Po-2

hasbeencalculatedtobe-1.0voltbyextrapolationofthe

correspondingpotentialsofzotherGroup6Belements.11

BivalentPoloniumBivalentPochlorideandbromidehavebeen

preparedonamilligramscale.jInsolutionthesecompoul@sare

subjecttooxidationbythepkoductsoftheintensealpha

bombardment,hereafterreferredtoasautooxidation.The

monoxideandmonosulfidehavealsobeenprepared,andboth

demonstratethesametendencytoeutooxidize.Abivalentpolonium

sulfatehasprobablyb