金属离子显色特征（电子化合物材料）

认识和开发富电子的电子化合物，有望为各类电子和催化应用领域提供新的机会。

来自北京高压科学研究中心的缑慧阳教授和东京理工大学的Hideo Hosono教授领导的团队，开发了一种基于几何识别和高通量从头算的材料筛选策略，以从各种化学计量的钇/钪氯化物(Y(Sc)xCly，y:x<2)及其组合物中识别出新的一类准1D、2D电子化合物。他们发现这些材料具有独特的特征，比如R-Cl紧密堆积结构（R为Y或Sc）和八面体骨架拓扑结构，在这个八面体框架拓扑中发现了阴离子电子。他们通过[YCl] ∙e−和[ScCl] ∙e− 准2D电子化合物和 [Y2Cl3] ∙e−、[Sc7Cl10] ∙e−、[Sc5Cl8]2 ∙2e−以及二价金属元素(Sc2 :3d1和Y2 : 4d1)准1D电子化合物而精确地量化了电子化合物的各种电子维数。准1D、2D电子化合物的局部阴离子电子被限制在内层空间中，而不象A2B-型2D电子化合物（如Ca2N）那样在层间空间中。此外，当氢原子被引入主体结构形成YClH和Y2Cl3H时，产生的相转变为常规的离子化合物，但由于费米能级的增加而表现出惊人的功函数降低，这与迄今为止报道的常规电子化合物相反。其中的Y2Cl3就与所分析的其他带有铁磁性的电子化合物不同，它是一个半导体，实验测得其带隙为1.14 eV 。这些结果可能有助于促进新的电子化合物材料的理性设计和理性探索，为后续技术应用奠定基础。

该文近期发表于npj Computational Materials 4: 77 (2018)，英文标题与摘要如下，点击https://www.nature.com/articles/s41524-018-0136-1可以自由获取论文PDF。

Identifying quasi-2D and 1D electrides in yttrium and scandium chlorides via geometrical identification

Biao Wan, Yangfan Lu, Zewen Xiao, Yoshinori Muraba, Junghwan Kim, Dajian Huang, Lailei Wu, Huiyang Gou, Jingwu Zhang, Faming Gao, Ho-kwang Mao & Hideo Hosono

Developing and understanding electron-rich electridesoffers a promising opportunity for a variety of electronic and catalyticapplications. Using a geometrical identification strategy, here we identify anew class of electride material, yttrium/scandium chlorides Y(Sc)xCly (y:x<2). Anionic electrons are found in the metal octahedralframework topology. The diverse electronic dimensionality of these electridesis quantified explicitly by quasi-two-dimensional (2D) electrides for [YCl] ∙e− and[ScCl] ∙e− and one-dimensional (1D) electrides for[Y2Cl3] ∙e−, [Sc7Cl10] ∙e−,and [Sc5Cl8]2 ∙2e− withdivalent metal elements (Sc2 : 3d1 and Y2 :4d1). The localized anionic electrons were confined withinthe inner-layer spaces, rather than inter-layer spaces that are observedin A2B-type 2D electrides, e.g. Ca2N. Moreover,when hydrogen atoms are introduced into the host structures to form YClH and Y2Cl3H,the generated phases transform to conventional ionic compounds but exhibited asurprising reduction of work function, arising from the increased Fermi levelenergy, contrary to the conventional electrides reported so far. Y2Cl3 wasexperimentally confirmed to be a semiconductor with a band gap of 1.14eV. These results may help to promote the rational designand discovery of new electride materials for further technologicalapplications.