Antimony cationic species

Solutions of many antimony and bismuth salts hydrolyse when diluted the cationic species then present will usually form a precipitate with any anion present. Addition of the appropriate acid suppresses the hydrolysis, reverses the reaction and the precipitate dissolves. This reaction indicates the presence of a bismuth or an antimony salt. 

Although twinning is a form of stress relief in crystals, it is also a means of changing the anion to cation stoichiometry and, more importantly in this system, may be the means by which sites with different coordination to the normal crystal matrix are achieved. Such an alteration would change the chemical properties of this localized region and thereby be of potential influence in the catalytic properties of the material. In particular, it could relate to the accommodation of cationic species in unusual or lower oxidation states and be relevant to the formation of specific active sites. Attention must therefore be given to a detailed consideration of the cationic oxidation states in the tin-antimony oxide catalyst, particularly in the solid solution phase. 

Closer inspection of the Sb Mossbauer parameters (79, 19a) showed that the decreasing antimony(V) chemical isomer shifts with decreasing antimony content in materials calcined for long periods or at high temperatures were consistent with increasing electron density at the antimony nuclei. Such data are compatible with the accumulation of electron density over the cationic species as the antimony content approaches 10%. It has... 

Treatment of methyl phenyl sulfoxide with diethylaminosulfur trifluoride (DAST), in the presence of antimony trichloride provides 159 in quantitative yield (66). The reaction proceeds in good yield with dialkyl sulfoxides and alkyl aryl sulfoxides (163). Reoxidation of the a-fluorosulfide (165) to the corresponding sulfoxide (161), followed by pyrolysis, provides a direct synthesis of fluoroolefins (65). The reaction is believed to proceed by a Pummerer-type mechanism (l.e., a fluoro-Pummerer reaction, Scheme 48). Similarly, Umemoto (67) reported that N-fluorocollidine (167) converted sulfides to ot-fluorosulfides (170) presumably via an S-fluorosulfonium cation species 168 (Scheme 49). The synthetically challenging fluorovinyl ether nucleosides (175) and (176) were prepared using the fluoro-Pummerer reaction (Scheme 50) (60) the (E)-isomer (175) could be isomerized to 176 under photolytic conditions. Finch and co-workers (69) converted 160 to the sulfoximine 178 and demonstrated the utility of this compound as a mild fluoromethylene synthon (Scheme 51). Base-catalyzed condensation 178 with a carbonyl compound gave 179 which afforded... 

Harada, T., Ohno, T., Kobayashi, S., and Mukaiyama, T. 1991. The catalytic Friedel-Crafts acylation reaction and the catalytic Beckmann rearrangement promoted by gallium(Itl) or an antimony(V) cationic species. Synthesis 1216-1220. 

A cationic species has been assumed to be present in a number of compounds formed from solvent molecules and various acceptor fluorides, such as antimony (V) fluoride. By analogy with the structure of IClsSbCls which contains chlorine bridges i with still discrete ICl2-groups... 

My work on long-lived (persistent) carbocations dates back to the late 1950s at Dow and resulted in the first direct observation of alkyl cations. Subsequently, a wide spectrum of carbocations as long-lived species was studied using antimony pentafluoride as an extremely strong Lewis acid and later using other highly acidic (superacidic) systems. 

The triatomic cations are usually prepared from the corresponding interhalogen, by reaction with a halogen acceptor molecule. This is impossible for some of the more exotic species which have no interhalogen precursor. For example, the [Br3]+ cation has been characterized20 in [Br3]+[AsF6], formed from the interaction of arsenic pentafluoride and a bromine/bromine pentafluoride mixture and the [Cl FJ cation results from the interaction of antimony pentafluoride with chlorine monofluoride.21... 

The first cyclopentadienyl n complexes of phosphorus, arsenic, and antimony have been characterized only recently. The salt-like species LXXXV-LXXXVII containing a cationic n complex are prepared via halide ion abstraction from pentamethylcyclopentadienyl element halides according to Eq. (47) (248-250). 

The electrodeposition of antimony, Sb, has been reported in both acidic and basic BPCI-AICI3 ionic liquid [28, 29]. Antimony trichloride, SbCl3, is soluble in both acidic and basic ionic liquids. In the case of an acidic ionic liquid, a cationic trivalent antimony species, SbClJ, is formed and can be reduced to the metallic state ... 

Pg (126) have been reported as products of the reaction of the elements with S2O6F2 HSO3F or with oleum. However, the ultraviolet spectra reported for these species are very similar to those found for Sg , or S4 ", and it seems very probable that antimony, arsenic, and phosphorus reduce HSO3F and H2S2O7 to elemental sulfur, which is then oxidized to Sig " ", Sg, or 84 +. Indeed, it has been demonstrated that elemental sulfur is one of the products of the reduction of oleum by antimony (123). Thus there is at present no reliable evidence for any polyatomic cations of P, As, or Sb, with the exception of (Sb ) . 

The species, SeJ and TeJ, appear to be square-planar like whose similarity is supported by theoretical calculations that treat all of them as 6-ir electron systems.The yellow selenium cation is obtained by treating elemental selenium with fluorosulfuric acid, fuming sulfuric acid, sulfur trioxide, disulfuric acid, or antimony pentafluoride. The red tellurium cation is obtained simi-larly. = ... 

---