Exotic compounds of monovalent calcium synthesized at high pressure  

作　　者：Jun Kong Kaiyuan Shi Artem R.Oganov Jiaqing Zhang Lei Su Xiao Dong 

机构地区：[1]Key Laboratory of Weak-Light Nonlinear Photonics and School of Physics,Nankai University,Tianjin 300071,China [2]Center for High Pressure Science and Technology Advanced Research,Beijing 100093,China [3]Skolkovo Institute of Science and Technology,Skolkovo Innovation Center,Bolshoy Boulevard 30,Building 1,Moscow 121205,Russia [4]Key Laboratory of Photochemistry,Institute of Chemistry,University of Chinese Academy of Sciences,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Matter and Radiation at Extremes》2024年第6期105-113,共9页极端条件下的物质与辐射（英文）

基　　金：supported by the National Science Foundation of China(Grant Nos.92263101,12174200,21627802,51722209,and 21273206);the Science Challenge Project(Grant No.TZ2016001);the Key Research Project of Higher Education(Grant Nos.15A140016 and 2010GGJS-110);the National Key R&D Program of China(Grant No.YS2018YFA070119);supported by the Russian Science Foundation(Grant No.24-43-00162)。

摘　　要：It is well known that atoms of the same element in different valence states show very different chemical behaviors.Calcium is a typical divalent metal,sharing or losing both of its valence electrons when forming compounds.Attempts have been made to synthesize compounds of monovalent calcium ions for decades,but with very little success(e.g.,in clusters).Pressure can result in substantial changes in the properties of atoms and chemical bonding,creating an extensive variety of unique materials with special valence states.In this study,using the ab initio evolutionary algorithm USPEX,we search for stable calcium-chlorine(Ca-Cl)system compounds at pressures up to 100 GPa.Besides the expected compound CaCl_(2),we predict three new compounds with monovalent Ca to be stable at high pressures,namely,CaCl,Ca_(5)Cl_(6),and Ca_(3)Cl_(4).According to our calculations,CaCl is stable at pressures above 18 GPa and is predicted to undergo a transition from nonmagnetic Fm-3m-CaCl to ferromagnetic Pm-3m-CaCl at 40 GPa.Ca_(5)Cl_(6)and Ca_(3)Cl_(4)are stable at pressures above 37 and 73 GPa,with space groups P-1 and R-3,respectively.Following these predictions,we successfully synthesized Pm-3m-CaCl in laser-heated diamond anvil cell experiments.The emergence of the unusual valence state at high pressures reveals exciting opportunities for creating entirely new materials in sufficiently large quantities for a variety of potential applications.

关 键 词：valent VALENCE entirely 

分 类 号：TQ131.22[化学工程—无机化工]