Downshift of d-states and the decomposition of silver halides  

作　　者：Yanlei Geng Jianfu Li Zhaobin Zhang Yang Lv Mengxin Lu Mengyuan Zhu Yong Liu Jianan Yuan Qingyang Hu Xiaoli Wang 

机构地区：[1]School of Physics and Electronic Information,Yantai University,Yantai 264005,China [2]Center for High Pressure Science and Technology Advanced Research,Beijing 100193,China

出　　处：《Matter and Radiation at Extremes》2024年第6期114-120,共7页极端条件下的物质与辐射（英文）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11974154,12304278,and T2425016);the Taishan Scholars Special Funding for Construction Projects(Grant No.TSTP20230622);the Natural Science Foundation of Shandong Province(Grant Nos.ZR2022MA004 and ZR2023QA127);the Special Foundation of Yantai for Leading Talents above Provincial Level。

摘　　要：The ionicity of ionic solids is typically characterized by the electronegativity of the constituent ions.Electronegativity measures the ability of electron transfer between atoms and is commonly considered under ambient conditions.Howeve r,external stresses profoundly change the ionicity,and compressed ionic compounds may behave differently.Here,we focus on silver halides,with constituent ions from one of the most electropositive metals and some of the most electronegative nonme tals.Using first-principles calculations,we find that the strengths of the ionic bonds in these compounds change greatly under pressure owing to downshifting of the Ag 4d-orbital.The center of this orbital is lowered to fill the antibonding state below the Fermi level,leading to chemical decomposition.Our results suggest that under pressure,the orbital energies and correspondingly the electronegativities still tune the ionicity and control the electron transfer,ionicity,and reactivity of both the metal and the nonmetal elements.However,the effects of orbital energies start to become dominant under pressure,causing substantial changes to the chemistry of ionic compounds and leading to an unusual phenomenon in which elements with substantial electronegativity differences,such as Ag and Br,do not necessarily form ionic compounds,but remain in their elemental forms.

关 键 词：SILVER ORBITAL BONDS 

分 类 号：TQ131.22[化学工程—无机化工]