Metal-Metal Bonded Compounds of the Early Transition Metals

科贝特9510278 在富金属卤化物和硫属化合物的早期过渡金属和这些材料的物理特性之间的合成探索将被追求的新材料。这些研究将以高度还原的化合物的独特组为特色，其中金属簇和凝聚簇相通过强结合的间隙元素稳定。簇主体将包括钪、钇和镧系元素，卤化物将是氯、溴和碘，硫属元素包括硫、硒和碲。卤化物中的卤化物以过渡金属为特征。进一步表征的显然是金属镧系元素为基础的化合物和它们的电子和磁性转变的性质将强调与搜索其他阶段显示不寻常的性能和新的结构和键合。 感兴趣的相的物理性质将被定义的晶体结构，电导率，磁化率，和光电子能谱测量和扩展休克尔（带）计算增强。特别强调的是键合的性质和物理性质，以及固态化学的新视野。 %对新材料的需求已得到充分认识。本计划的长期目标是扩展固态可能的边界，理解和概念化稳定性，结构，键合和性能的结果，并最终提供足够的信息和经验，以允许一些系统化和合理的预测。提出了几个新的和令人兴奋的方向。新的重点包括镧的二元、三元和四元（间隙）化合物，镧是一种研究很少但似乎表现出一些独特和显着化合物的元素 *

Corbett 9510278 Synthetic explorations will be pursued for novel materials among the metal-rich halides and chalcogenides of the early transition metals and the physical characterization of these materials. The studies will feature the unique group of highly reduced compounds in which metal cluster and condensed cluster phases are stabilized by strongly bound, interstitial elements. The cluster hosts will include scandium, yttrium and the lanthanides, the halides will be chlorine, bromine and iodine, the chalcogenides sulfur, selenium and tellurium. The interstitials in halides will feature the transition metals. Further characterization of the apparently metallic lanthanides-based compounds and of the nature of their electronic and magnetic transitions will be emphasized together with searches for other phases showing unusual properties and new structures and bonding. Physical properties of interesting phases will be defined by crystal structure, conductivity, magnetic susceptibility, and photoelectron spectroscopic measurements and augmented by extended-Huckel (band) calculations. Particular emphasis will be given to the nature of the bonding and the physical properties and to new horizons in solid state chemistry. %%% The need for new materials is well recognized. The long range objectives of the present program are to expand the boundaries of what is possible in the solid state, to understand and conceptualize the results as to stability, structure, bonding and properties and, ultimately, to provide sufficient information and experience to allow some systemization and reasonable predictions. Several new and exciting directions are proposed. The new emphases include binary, ternary and quaternary (interstitial) compounds of lanthanum, an element that has been investigated very little but which appears to exhibit some distinctive and remarkable compounds ***