简介:ThespinelLiMn2O4-x(SO4)xcompoundcathodematerialsweresynthesizedbysolid-statereactionofthecalculatedamountsofLiOH·H2O,MnO2andMnSO4.Theresultsoftheelectrochemicaltestdemonstratedthatthesematerialsexhbitedexcellentelectrochemicalproperties.Thehighestreversiblecapacityoftheseseriesofcathodematerialswas-120mAh/g,andafter50cycles,thisreversiblecapacitywasstillaround116mAh/gwithnearly100%reversibleefficiency,whichrevealedthatdopedsulfateioncouldimprovethestructuralstabilityofspinel.
简介:Auranylcompound,K4UO2(CO3)3hasbeencharacterizedbypowderX-raydiffractionmethod.M.W.=606.46,monoclinic,C2/c(No.15),a=1.0240(7),b=0.9198(4),c=1.2222(12)nm,β=95.12(4)°,V=1.1466(5)nm3,Z=4,Dm=3.468g/cm3,Dc=3.513g/cm,λ(CuKα1)=O.1540598nm,T=298K.ThestructurewassolvedbyheavyatommethodandFouriersynthesis,andrefinedbyfull-matrixleast-squaresmethodtoR=0.1185for275reflections.Theuranium(Ⅵ)atomisinaneight-coordinatedistortedhexagonal-bipyramidalenvironmentwithcreasyfanshape.Thelinearuranylgroupapproachestoperpendiculartotheequatorialplaneinwhichthreecarbonategroupsarechelated.U(Ⅵ)hastwolinearoxygenatomsclosertoit(U-O=0.1767(5)nm)thansixotherneighbours(U-Orangingfrom0.2516to0.2568nm).Thedistancesbetweencarbonatomsanduncoordinatedoxygenatomsare0.122(1)and0.123(1)nm,whicharedistinctlydifferentfromthosebetweencarbonandcoordinatedoxygenatoms(mean0.134(6)nm).Thisfactrevealsthenon-eq-uivalenceofoneoxygenatomtotheothertwoineachcarbonate.InK4UO2(CO3)3,theO-Odis-tancefortheadjacentcarbonategroupsis0.2794(4)nmapproachingtothesumofVanderWaalsradiioftwooxygenatoms.TheK-Odistancesvarybetween0.2667and0.3131nm,andeachanionisimmediatelysurroundedbysixpotassiumions,onlyfourofwhichcanbeconsideredtobelongtothesamestructuralformulaunit,andtheyaresymmetricallylocatedaboveandbelowtheequatorialplane.
简介:AnovelcrystalcharacterizationinstrumenthasbeenbuiltupinwhichacombinationofX-raymultiplediffractionandX-raytopographyisappliedtoenablingthecross-correlationbetweenmicro-crystallographicsymmetryanditsspatialdependenceinrelationtolatticedefects.Thisfacilityisusedtoexamine,inaselfconsistentmanner,growthsector-dependantchangestoboththecrystallographicstructureandthelatticedefectsassociatedwiththeactionofhabit-modifyingadditivesinanumberofrepresentativecrystalgrowthsystems.Inaddition,thenewinstrumentcanbeusedtoprobemicro-crystallographicaspects(suchasdistortiontocrystalsymmetry)andrelatetheseinaspatiallyresolvedmannertothecrystaldefectstructureincrystalsdopedwithknownhabitmodifiers.
简介:Aseriesoftitlecompoundsaswellastheirprecursorsweresynthesizedbyprecursorroute.TheirPXRDpatternswerecharacterizedwithZrW2O8orZrMo2O8modelbyRietveldmethod.Thethermalcontractionsofthecompoundsweredeterminedaccordingtothevariable-temperaturePXRDdataandNTEcoefficientswerepresented.Thetwo-phasemixtureofZrW0.4Mo1.6O8wasalsoanalyzedindividually.
简介:ThehydrolysisofcephanoneinTritonX-100micelleandTritonX-100/n-C5H11OH/H2O(O/W)microemulsionwerestudiedbymeansofUV-Visabsorptionspectroscopy.Theresultsshowthatcomparedwithwater,TritonX-100micelleandTritonX-100/n-C5H11OH/H2O(O/W)microemulsioncaninhibitthehydrolysisofcephanone.TheinhibitioneffectsofTritonX-100micelleandTritonX-100/n-C5H11OH/H2O(O/W)microemulsiononthehydrolysisofcephanonearerelatedtothelocationofcephanoneintheinterphasesofTritonX-100micellesandTritonX-100/n-C5H11OH/H2O(O/W)microemulsiondroplets.
简介:Twoseriesofmixedoxides,CoAlMandMgAlM(M=Cr,Mn,Fe,Co,Ni,Cu),werepreparedbycalciningtheircorrespondinghydrotalcite-likecompounds(HTLc).TheratioofMg:Al:M(orCo:Al:M)was3:1:1.ThecatalyticactivityofallsamplesforthereactionofNO+COwasinvestigated.TheresultsshowedthattheactivityofCoAlMwasmuchhigherthanthatofMgAlM.ThestructureandthepropertyofredoxwerecharacterizedbyXRDandH2-TPR.TheresultsindicatedthatonlyMgOphasewasobservedaftercalciningMgAlMhydrotalcites,andthetransitionmetalsbecamemorestable.Thespinel-likephaseappearedinallofCoAlMsamplesafterthecalcination,andthetransitionmetalswerechangedtobemoreactive,andeasilyreduced.TheactivitiesofthreeseriesofmixedoxidesCoAlCuobtainedfromdifferentpreparationmethods,differentratioofCo:Al:Cuandatdifferentcalcinationtemperatures,werestudiedindetailforproposingthemechanismofreaction.TheabilityofadsorptionofNOandCO
简介:Tris)(η5-cyclopentadienyl-μ-carbonyl-iron)-μ3-nitrosylclusterwasobtainedfromthereactionofcyclopentadienyldicarbonylirondimerwithnitrogenmonoxideinxylene.Theclusterwascharacterizedbyelementalanalyses,IR,MSand1HNMR.Thecrystalstructureof[(η5-C5H5)(μ-CO)Fe]3(μ3-NO).C4H8OwasdeterminedbyX-raydiffractionanalysis.ItcrystallizesintheorthorhombicspacegroupPnma,a=9.053(2),6=10.545(2),c=22.525(4)A,V=2150.3(7)A3,Z=4,Dc=1.68g.cm-3;structuresolutionandrefinementbasedon1141reflectionswithI>3.0(I)(MoKa,A=0.71073A)convergedatR=0.0540.Theinfraredabsorptionbandat1325cm-1oftheμ3-NOinthecluster,whichisredshifted,showsthatμ3-NOisactivated.