New Synthetic High-Density Nickel Sulfide: A Plausible Component of the Earth's Core and Terrestrial Planets

摘要

New phase Ni_(3-x)S with a structural type of Ni_3P in equilibrium with metallic nickel was synthesized in the subsolidus area of pseudo-binary system Ni-Ni_3S_2 at a temperature of 800℃ and hydrostatic pressure of 20 GPa. This phase is stable at a pressure >9-10 GPa. The structural analogy with the high-density Fe_3S phase allows us to assume the existence of wide area of solid solutions (Fe,Ni)_3S, which should be accounted for in the models of core composition of the Earth and other planets.