Antimony electron diffraction

Silicon forms a series of compounds with antimony analogous to silane. Trisilylstibine, Sb(SiH3)3, has been shown to be pyramidal by electron diffraction.95 There was no evidence of bond angle widening, nor bond shortening, thus suggesting the absence of (p — d)n bonding. The silylstibines are prepared by conventional methods (equation 25). 

Mechanism. The interaction of antimony with supported nickel particles was studied with X-ray diffraction (XRD) (10) These studies suggested that a high level of antimony is present on the surface of Ni-Sb alloys. Further studies of the Ni-Sb alloy, using X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES), confirmed the presence of an antimony enriched surface (.11) The surface enrichment of antimony on the Ni-Sb alloy would be expected to significantly alter the catalytic activity of nickel, as indeed occurs when antimony is added to nickel laden cracking catalysts. 

X-ray diffraction data. However, the observation by electron microscopy 12, 32) of twinned microcrystals in tin(IV) oxides containing a low concentration of antimony could be consistent with the accommodation of antimony(III) in more favorable sites and would be compatible with the observed migration of antimony away from the tin rich species and the formation of a mixed oxide with similar lattice parameters to tin(IV) oxide. However, the charge transfer spectrum would still require some Sb ions to occupy octahedral sites, and whether or not such accommodation could be achieved at or near the twin boundaries is not clear (32). 

The segregation phenomena in V-Sb-0 catalyst for selective propylene oxidation to acrolein were studied by means of X-ray photoelectron spectroscopy, scanning electron microscopy with EDS, as well as electron and X-ray diffraction. The vanadium antimonate crystals were found to be a main component of the catalyst. It was stated that epitaxial layers of antimony tetroxide on the base faces of vanadium antimonate crystals, exposing (010) plane, were responsible for high catalyst selectivity. 

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