Novel Stable Stoichiometries In Molybdenum-Phosphorus Phase Diagrams Under Pressures

In recent years,metal phosphides have attracted much attention for their potential applications in the semiconductor and catalyst industries.Among them,molybdenum phosphate has excellent physical and chemical properties and peculiar structural characteristics,and the systematic study of molybdenum phosphate is of great significance,which is beneficial to enhance people's understanding of molybdenum phosphate,better play its application in industrial industry,and better serve human beingsIn this paper,we explore the thermodynamically stable and metastable phases of molybdenum phosphides under ambient pressure up to 200GPa using an evolutionary algorithm for crystal structure prediction combined with first-principles density functional theory calculations.The Mo simple substance is stable in the pressure range of 0-200GPa and no structural phase transition occurs.The P-monoplasm is more active and the structure changes under a given pressure.All experimentally synthesized Mo-M structures were found at atmospheric pressure,namely thermodynamically stable Mo3P,MoP,M0P2 and MoP4 as well as metastable Mo8P5 and Mo4P3 phases.When the pressure increased from 0 to 200GPa,five thermodynamically stable chemical phases emerged:Mo4P,Mo2P,Mo8P5,Mo4P3,and phosphorus-rich phase Mo2P3.Valence electron concentrations,such as the ratio of molybdenum atoms to phosphorus atoms,play a crucial role in the covalent grid dimension of phosphorus.Pressure acts as adhesive in the phosphide mesh,which makes possible the emergence of new kinetic and thermodynamically stable phases These structures contain phosphides of isolated P3-ions,types of molecular P2,linearly infinitely electron-deficient phosphorus chains or curved phosphorus layers The calculation found that at 63GPa,the MoP was transformed from a WC-type structure to a CsCl-type structure.While the other components exhibited a single phase in the range of thermodynamic stability pressure without a phase transition.All stable molybdenum-phosphorous phases were found to be metal phasesIn summary,we systematically studied the crystal structure,thermodynamic stability,and bonding modes between P-P of Mo-P systems.These results are not only helpful to fully understand the compounds of Mo-P system and their applications,but also important for understanding the bonding of p in metal phosphides.