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Lanthanides belong to the sixth cycle of the periodic table Ⅲ B family, are all solid metal, they are La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, holmium, erbium, thulium, ytterbium, and lutetium were 15 kinds of metals and their periphery are two layers of electronic 5d16s2, while the peripheral third layer f orbital but never zero to 14, so the external electronic structure of 4f0-145d16s2, and therefore these elements in oxidation number are to 3, very close chemical properties, extraction, when it is difficult to separate them they are mostly multi-element mineral mix, more difficult to increase refining, and their atomic number of 57-71, one by one to increase the number of protons the nucleus, and thus extranuclear electron of gravity is also growing, so that atomic radius decreases with increasing atomic number Z, which makes lanthanides contraction, ionic radius is also reduced, which also makes Zr, Hf, Nb and Ta, Mo and W, the atom and ionic radius very close to each other they also determine a similar nature, resulting in difficult separation, also the tribe Ⅷ of the fifth cycle, ruthenium, rhodium, palladium, and the sixth cycle, osmium, iridium, platinum is very similar in nature, thus The six elements, said platinum group elements.
镧系元素属于周期表第六周期中ⅢB族,全部是固体金属,它们是镧、铈、镨、钕、钷、钐、铕、钆、铽、镝、钬、铒、铥、镱和镥共十五种金属元素,它们的外围两层的电子均是5d16s2,而外围第三层的f轨道电子却从零增加到14个,所以外围电子结构为4f0-145d16s2,而使这些元素氧化数均为+3,化学性质极为接近,提炼时很难分开,它们的矿石又大多是多种元素混在一起的,更增加提纯难度,它们的原子序数为57-71,核内质子数逐个增加,因而对核外电子引力也不断增强,使原子半径随原子序数Z增加而减小,这就使镧系元素收缩、离子半径也缩小,这也使得Zr和Hf,Nb和Ta、Mo和W等原子和离子半径都很接近、也决定了它们彼此性质类似,以致难以分离、也使第Ⅷ族中第五周期的钌、铑、钯和第六周期的锇、铱、铂在性质上极为相似,因而称这六个元素为铂系元素。
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Tache of kinetics for the procedure of reduction reaction of samarium oxide with metallic lanthanum has been discussed in this paper.
讨论了镧热还原氧化钐过程的动力学环节,分析了还原过程镧—钐合金存在的可能性,采用反证法确定了制备金属钐温度下的动力学控速环节。
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When diaryl ketones were treated in DMF promoted by samarium metal with TMSCl as activator, diaryl ketones react with DMF followed by a carbene rearrangement to afford benzoins unexpectedly, with benzils were obtained as byproducts, the formation of which may be explained as a result arising from the auto-oxidation of benzoins. Further investigation found the reaction could also proceed smoothly when I〓 was used as an activator. The reaction could occur as well in SmI〓/THF, though benzoins were obtained in relatively low yields.
发现当有活化剂TMSCl存在时,金属钐能有效的促进二芳酮和DMF的发生反应,偶联后发生卡宾重排,意外地得到苯偶姻类化合物,同时伴随着少量的二芳基二酮副产物生成,我们推测二芳基二酮的生成可能从苯偶姻的自氧化而来;进一步的研究表明,用一定量的I〓活化金属钐,该反应也可以顺利的进行,并且可以得到相对更好的实验结果。
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TiO:一氧化钛
rO2)、一氧化钛(TiO)、五氧化三钛(Ti3O5)、二氧化硅(SiO2)、二氧化铪(HfO2)、二氧化钛(TiO2)、三氧化二钛(Ti2O3)、(Ti2O3)、五氧化二铌(Nb2O5)、三氧化二铝(Al2O3)、氧化镁(MgO)、氧化钇(Y2O3)、氧化钐(Sm2O3)、氧化镨(Pr6O11)、氧化钨(WO3)、氧化锑(Sb2O3)、氧化镍(Sb2O3)、三氧化二铁(Fe2O3)、氧化锡(SnO2+Pt(0.5~1%))、二
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samarium oxide:氧化钐
samarium nitride 氮化钐 | samarium oxide 氧化钐 | samarium silicate 硅酸钐
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ferrites:铁氧体
铁氧体(BaFeO)、钐钴5(SmCo)等,...铁氧体(ferrites) 铁氧体是一种非金属磁性材料,又叫铁淦氧. 它是由三氧化二铁和一种或几种其他金属氧化物(例如:氧化镍、氧化锌、氧化锰、氧化镁、氧化钡、氧化锶等)配制烧结而成. 它的相对磁导率可高达几千,