STRUCTURE OF B6O BORON-SUBOXIDE BY RIETVELD REFINEMENT

The structures of the B6O samples prepared by oxidizing boron with ZnO at temperatures of 1350-1500-degrees-C in an argon atmosphere have be en refined by the Rietveld method. The B6O samples were found to conta in an amorphous phase from their X-ray diffraction profiles in additio n to B6O diffraction peaks. The results indicate that the B6O samples, space group R3mBAR, no.166, a(hex) = 0.5367(l) nm and c(hex) = 1.2328 (2) nm in the hexagonal unit cell, have oxygen deficiencies with 0.76( 6) oxygen occupancy. A radial distribution function method applied to an extracted portion of the amorphous phase, suggests that each amorph ous phase has nearly similar short-range order structure to that of th e alpha-tetragonal boron type rather than to those of any other relate d boron phases.