Lin Jianyan, Zhao Ziyuan, Liu Chunyu, Zhang Jing, Du Xin, Yang Guochun, Ma Yanming
Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory for UV Light-Emitting Materials and Technology of Ministry of Education , Northeast Normal University , Changchun 130024 , China.
State Key Laboratory of Superhard Materials, College of Physics and International Center of Future Science , Jilin University , Changchun 130012 , China.
J Am Chem Soc. 2019 Apr 3;141(13):5409-5414. doi: 10.1021/jacs.9b00069. Epub 2019 Mar 21.
An important goal in chemistry is to prepare F-rich transition metal fluorides due to the high oxidation states and potential applications such as oxidating and fluorinating agents. Thus far, the highest F stoichiometry in the neutral transition metal fluorides is 7. Here, we identify a hitherto unknown IrF compound through first-principles swarm-intelligence structure search calculations under high pressure. The three identified IrF phases exhibit typical molecular crystal characters, showing +8 oxidation state in Ir. The spatial symmetry of the basic building block in the three IrF phases gradually increases with pressure (e.g., dodecahedron [Formula: see text] square antiprism [Formula: see text] quasicube). The pressure-induced faster increase of Ir 5d orbital energy level with respect to F 2p provides a strong charge transfer driving force from Ir 5d to F 2p, facilitating the formation of F-rich compounds. More interestingly, the predicted electron affinities of the three predicted IrF phases are comparable/larger than that of PtF, the strongest oxidation agent in the third row transition metal hexafluorides. The built high-pressure phase diagram of Ir-F binary compounds provides useful information for experimental synthesis.
由于高氧化态以及诸如氧化剂和氟化剂等潜在应用，制备富氟过渡金属氟化物是化学领域的一个重要目标。到目前为止，中性过渡金属氟化物中最高的氟化学计量比为7。在此，我们通过高压下的第一性原理群体智能结构搜索计算，确定了一种迄今未知的IrF化合物。所确定的三个IrF相表现出典型的分子晶体特征，Ir呈现+8氧化态。三个IrF相基本结构单元的空间对称性随压力逐渐增加（例如，十二面体[化学式：见原文] 正方反棱柱[化学式：见原文] 准立方体）。压力诱导的Ir 5d轨道能级相对于F 2p更快增加，提供了从Ir 5d到F 2p的强大电荷转移驱动力，促进了富氟化合物的形成。更有趣的是，预测的三个IrF相的电子亲和能与第三行过渡金属六氟化物中最强的氧化剂PtF相当/更大。构建的Ir-F二元化合物高压相图为实验合成提供了有用信息。
