High pressure induced decomposition of antimony trisulfide

Abstract

Recently, high pressure (HP) experiment discovered that a conventional Bi2S3 compound was unstable and decomposed into new stoichiometric BiS2 and BiS upon compression, inspiring our efforts to evaluate this decomposed view in other V-VI A2B3 compounds. By combing crystal structure prediction with first-principle calculations, here the HP behavior of antimony trisulfide (Sb2S3) was investigated in order to testify whether or not it can also be driven to decompose into new stoichiometry. As expected, the Sb2S3 compound was found to be only stable up to 36 GPa, above that, it is also decomposed into two new stoichiometries SbS2 (Cmca) and SbS (Pm-3m). Interestingly, before this decomposition, a novel disordered bcc-like phase P4bm-Sb2S3 is uncovered for the first time. Upon reaching to 69 GPa, another decomposition reaction of SbS2→SbS+S is revealed to occur in the Sb-S compounds. Our findings give fresh insights into the HP activity of the Sb2S3 compound and deepen the understanding of pressure-induced decomposition in the group of V-VI A2B3 compounds.