Perchlorate disorder

The hrst X-ray crystal structure of a carbocation salt was reported in 1965. Triphenylmethyl perchlorate (27) has a planar central carbon. The three phenyl rings are each twisted 30°, so that overall the cation has a propellor shape. Disordered perchlorate anions sit above and below the central carbon, with a C—Cl separation of 4.09 A. 

The l-(hetero)arylvinyl-5//-2,3-benzodiazepines, useful for the treatment of central nervous system (CNS) disorders, are prepared by the reaction of 2-benzopyrylium perchlorates with hydrazine hydrate <2001EPP0726257B1>. 

However, the use of perchlorates in pyrotechnic formulations is discouraged due to the supposed toxicity of this chemical which has been linked to causing thyroid disorders. Furthermore, the combustion of polychlorinated organic materials such as poly(vinyl) chloride has been shown to produce polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). These polychlorinated chemicals are highly toxic and are potent carcinogens. Therefore, the removal of perchlorates and chlorinated organic materials in pyrotechnic formulations would eliminate the formation of these aforementioned pollutants. 

One moiety that almost invariably appears to be disordered in crystals is the perchlorate ion. There are numerous examples in the literature, particularly because of the well-known tendency of perchlorate to promote the... 

It is helpfiil to avoid, as far as possible, the solvents (especially dichloromethane) and anions (e g. perchlorate or triffate) that show a tendency to be disordered in the crystal stmcture. 

I. r. and Raman data are now available for (C6F,)3Sb and the dichloride and bromide,"" and structural studies have been reported for three p,-oxo-compounds (Me3SbX)20 (X = Cl, CIO4, or N3)."" All three species have no symmetry and are extensively disordered, but the antimony atoms have distorted trigonal-bipyramidal co-ordination. In the chloride and perchlorate, however, these groups... 

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