Pressure-Induced Novel Stable Stoichiometries in Molybdenum–Phosphorus Phase Diagrams under Pressure

The thermodynamically (meta)stable phases of molybdenum–phosphorus under pressure are explored at pressures from ambient up to 200 GPa using an evolutionary algorithm designed for crystal structure prediction combined with first-principles density functional calculations. All experimentally synthesized Mo–P structures are found at atmospheric pressure, namely, thermodynamically stable Mo3P, MoP, MoP2, and MoP4 and the metastable Mo8P5 and Mo4P3 phases. When pressure increases from 0 to 200 GPa, five thermodynamically stable stoichiometries emerge: Mo4P, Mo2P, Mo8P5, Mo4P3, and a phosphorus-rich phase, Mo2P3. In general, the Zintl–Klemm concept and molecular orbital analysis proved useful for rationalizing the structural, bonding, and electronic properties encountered in the covalent phosphorus-based units. While the valence electron concentration, e.g., the Mo/P ratio, plays a crucial role in phosphorus covalent net dimensionality, pressure acts as a bonding glue in the phosphide nets, enabling the emerge...