Antimony oxide clusters

Kaiser B, Bernhardt T M, Kinne M, Rademann K and Fleidenreich A 1999 Formation, stability, and structures of antimony oxide cluster ions J. Chem. Phys. 110 1437... 

Fig. 1.28. Mass spectra of antimony and antimony oxide cluster distributions synthesized at different oxygen partial pressures in the flow tube reactor presented in Fig. 1.27. (a) oxygen traces only, (b) 4mbar O2, (c) 40mbar O2. The geometric structures shown for the most prominent antimony oxide cluster species in the mass spectra have been determined by quantum chemical calculations (dark spheres, antimony atoms grey spheres, oxygen atoms) [23,163]...

France M R, Buchanan J W, Robinson J C, Pullins S FI, Tucker J T, King R B and Duncan M A 1997 Antimony and bismuth oxide clusters growth and decomposition of new magic number clusters J. Phys. Chem. A 101 6214... 

The oxidizing superacids are versatile and effective for the generation of clusters in solution but severe difficulties are associated with crystallization and recovery of solid cluster phases. These difficulties were to a great extent overcome by the observation that the pentaffuorides of antimony and, even better, arsenic in super-acidic or inert solvents quantitatively oxidize post-transition elements to cationic clusters. The method was presented in 1969 and was first used in the synthesis of the (AsFfi)" salt of (Ss)" 4 in HF solution, according to reaction (7). ° ... 

The syntheses of cationic bismuth clusters were described in Section 9.12. The [Bis] ion may also be obtained by oxidation of Bi using GaCls in benzene, or using AsFs. Although [Bis], [Big] and [Bi9] have been known for many years, no well-characterized example of a homopolyatomic antimony cation was reported until 2004. 

We have found that the main group metal and metalloid reductants mocury, bismuth, and antimony are highly effective " in reducing WCIe or M0CI5 at surprisingly lower temperatures than commonly used in the solid-state synthesis of early transition metal cluster halides. BorosUicate ampules can be substituted for the more expensive and less easily sealed quartz ampules at these lower temperatures, and the metals and metalloids are not as impacted by oxide coatings that inhibit sohd-state reactions with more active metals. These lower temperatures may allow access to kinetic products, such as trinuclear clusters, instead of thermodynamic products. 

Besides the use of vanadium-based catalysts, a wide variety of other catalyst compositions were reported. A recent review focussed on FeSbO based catalysts promoted by appropriate additives as suitable for the ammoxidation of alkyl-substituted aromatics and hetero aromatic compounds. A unique preparation method of a fluid-bed catalyst is presented using nitric acid oxidation of antimony trioxide catalyzed with iron ions. The catalysts thus prepared have superior catalytic and physical properties. [78]. In addition, some unique compositions were reported by different research groups. For instance, new ammoxidation catalysts based on rhenium carbonyl cluster complexes containing antimony and bismuth ligands were reported by Adam et al. [79]. Single-site multifunctional catalysts based on [Cu RUj C ] nanocluster anchored to inner walls of mesoporous silica were also used in the ammoxidation of 3P [80]. 

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