Mary B. Millikan

The alleged dipyridinium Fe(III) pentachloride and some related compounds

Abstract The compound dipyridinium Fe(III) pentachloride could not be prepared in aqueous solution as was previously reported, but the preparation yielded (C 5 H 6 N) 3 Fe 2 Cl 9 instead. A compound of formula (C 5 H 6 N) 2 )FeCl 5 can, however, be obtained using alcohol as solvent, although Mossbauer and low energy IR spectroscopic data suggest that this (and some related chloroferrate (III) species) are double salts containing the FeCl 4 − ion.

On the reported pyridinium pentachlorothallate(III) and some related compounds

Abstract While (C 5 H 6 N) 2 TlCl 5 cannot be prepared in water via the reported procedure it may be obtained in non-aqueous media. Although its low-energy infrared spectrum contains broad peaks and the Raman spectrum is deceptively simple, comparison of these spectra with those of other TlCl 4 − , TlCl 5 3− and TlCl 6 3− derivatives shows that (C 5 H 6 N) 2 TlCl 5 contains a genuine pentacoordinate TlCl 5 2− species which, however, appears to dissociate in dilute ethanol solution. While the related (C 5 H 6 N) 3 TlCl 6 contains a genuine TlCl 6 3− ion (C 5 H 6 N) 3 Tl 2 Cl 9 probably contains both TlCl 4 − and TlCl 5 2− in the solid. Reactions of (C 5 H 6 N) 2 TlCl 5 with dimethylsulfoxide, 2,2′-dipyridyl and 1,10-phenanthroline are described.