氧化物性质表\MgO热膨胀系数

substance:magnesiumoxide(MgO)26s01d04property:crystalstructure,latticeparameters,thermalexpansionForcrystalstructure,spacegroupetc.,seedocument26s00d1and26s00d3.Undernormalconditions,MgOcrystallizesintherocksalt(B1)structure.Thisstructurehasbeenfoundtobestableatleastupto227GPa[95D].Underpressure,theNaCl(B1)structuretransformsintotheCsCl(B2)structure.FromLCAO-HFcalculations,atthetransitionpressuretheinvertedNiAs(B81)structurehasanenergyverysimilartothatoftheCsClstructure[86C].equationofstate(pressure-volumerelation)Figs.1,2.Seealso[86M,96W,98M]forothercalculations.Forthedependenceofthevolumeasafunctionofpressure(p<35GPa),see[65P].Theequationofstate,elasticityandshearmodulusofMgOwereexaminedunderpressure[95D].transitionpressureandvolumechange(ptrinGPa)ptr220LCAO-HFcalculation86C580semiempiricalcalculation91Z∆V/V0.034latticeparameter(NaClstructure)(inÅ)a4.211X-raydiffraction63W4.370(16)T=2100°CX-raydiffraction72V4.191calculated84C4.201LCAO-HFcalculation86C4.192semiempiricalcalculation91Z4.16ab-initiopseudopotentialcalculation94S4.216T=298KX-raydiffractionmeasurements,77Hpowdersamples(forfurtherdataupto1055K,seeibid.)4.212(8)T=297KX-raydiffraction,singlecrystal68S1(furtherdataaslowas19.8Kin[68S1],similardatain[63P]and[64D],dataforpressuresbetween0and140kbarin[73S])Forthelatticeconstantfromanab-initioHFcalculationwithvariouscorrelationcorrections,see[94M].latticeparameter(CsClstructure)(inÅ)a2.573(p=0)LCAO-HFcalculation86C2.613(p=0)semiempiricalcalculation91Zlatticeparameter(invertedNiAsstructure)(inÅ)a2.900(p=0)LCAO-HFcalculation86Cc4.988linearthermalexpansioncoefficient(in10–6K–1)α0.61T=65Kcapacitancedilatometer,polycrystal69B0.78T=70K1.14T=80K1.58T=90K2.10T=100K2.61T=110K3.20T=120K3.86T=130K4.37T=140K4.95T=150K5.48T=160K6.00T=170K6.49T=180K6.95T=190K7.39T=200K7.8T=210K8.2T=220K8.5T=230K8.8T=240K9.1T=250K9.4T=260K9.7T=270K10.0T=280K10.2T=290K10.4T=300K10.6T=310K9.84T=283Kmeasurementinathree-terminal73Wcapacitancecell,singlecrystal;10.5T=300Kelectricalcapacitancetechnique;for66Wtemperaturedependencebetween20and300K,seeFig.3(furtherdataintherange20to1200Kin[66W];similarinformationin[64B,62G,63P,68S1,64D,77H,68S2])13.47T=293...573Kmeanvalue,X-raymeasurements(for57Bvaluesupto1500K,seeibid.)Seethecompilationofexperimentaldatapreviousto1977in[77T].Forabreathing-shellmodelmolecular-dynamicssimulationofthetemperature(0