Structure of a new high-pressure–high-temperature modification of antimony(III) oxide, γ-Sb2O3, from high-resolution synchrotron powder diffraction data

Abstract

A quenchable new high-pressure–high-temperature modification of antimony(III) oxide, γ-Sb2O3, has been obtained at hydrostatic pressures of 9–11 GPa and temperatures of 573–773 K. Its crystal structure has been determined from high-resolution synchrotron powder diffraction data. γ-Sb2O3consists of three-dimensionally cross-linked infinite chains of SbO3Eunits (E= lone pair) with the chains forming tetragonal rod-packing. The underlying topology of γ-Sb2O3(3,3T8) is found very rarely in inorganic structures; it is realised only for the polyanion [Si4O4N6]10−that occurs in the Ce4(Si4O4N6)O structure type. The structural relation to the two previously known polymorphs of Sb2O3at ambient pressure, valentinite and senarmontite is discussed.