问题标题:
【求关于水晶的英文短文RT,五六百个单词左右,最好有中文,没有也行不要太长啊】
问题描述:

求关于水晶的英文短文

RT,五六百个单词左右,最好有中文,没有也行

不要太长啊

李唐回答:
  ThePhysicsofaCrystal   Mostsimplechemicalcompoundsconsistofcrystals.Ifyouweretoexaminealumpofcrystallinematerialveryclosely,youwouldbeabletoseetinyindividualcrystals.Allcrystalshaveadefinitegeometricshape,determinedbythewaytheatomsarelinkedtogether.   Mineralogistsrecognize32differentclassesofcrystal,whicharegroupedintosevencrystalsystems.Crystalsystemsaredescribedbytheiraxis,whichareimaginarylinesthatjointhecenterofopposingfacesofacrystal.Forexample,ifacubiccrystalhasthreesetsofopposingfaces,ithasthreeaxes.Theyareallofequallengthandareallatrightanglestoeachother.   Cubiccrystalsaredescribedasbeingisometric,butnotallisometriccrystalsareplaincubes.Ifthecornersofacubearecutoff,theresultisapolyhedronwithsixoctagonalfacedandeighttriangularones.   Asidefromtheisometricsystem,thereisalso;atetragonal,orthorhombic,monoclinic,triclinicandhexagonalsystem.   Crystalsmayformwhenasolutionofasubstanceevaporates.Crystalsmayalsoformwhenavaporormoltensubstancesolidifies.   Allotropesaredifferentformsofthesameelement.ForExample,oxygenhastwoallotropes,normaloxygenandozone.Purecarbonalsohastwoallotropes,diamondandgraphite.Acrystalofdiamondisinfactasinglegiantmoleculeinwhicheverycarbonatomislinkedtofourother,byfourequal,strongbonds.Thesebondsarearrangedtetrahedrallyroundeachatomandtherearenoplanesalongwhichthegiantmoleculecaneasilybesplit.Thisqualityiswhatgivesdiamonditstremendoushardness.   Graphiteontheotherhand,consistsofflatsheetsofcarbonatomsarrangedinadjoiningrings.Eachcarbonatomislinkedtothreeothersbyfairlystrongbondthatalllieinthesameplane.Thesecaneasilybeovercome,allowingthesheetstoslideovereachother.Asaresult,graphiteisasoftslipperysubstancethatcanbeusedasalubricant.   【稍微短点了…………建议lz自己去外国搜索引擎找一找,比如yahoo、Google之类的,可以搜essaysoncrystal……稍微耐心点看,总能找到满意的^-^】
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《【求关于水晶的英文短文RT,五六百个单词左右,最好有中文,没有也行不要太长啊】|小学英语问答-字典翻译问答网》
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