Vibrational frequencies and force constants of some Group IVa and Group Va hexafluoride ions

Abstract

Inorganic Chemistry cess Ti02 was filtered from the solution before making the nmr measurements.In contrast to the report of Caglioti and co-workers2 and in agreement with Schmitt, et al.,s we find that the TiFe2_ ion is very stable in water. Over long periods of time only a sharp singlet is seen in the F19 nmr spectrum of the solution at room temperature. (NH4)2-TiFe in a 10% HC1 solution was prepared and examined by nmr spectroscopy. The spectrum showed the presence of TiF5-H20-and TiF62~. These species were in a 2:3 ratio. The formation of TiF5-H20~is suggested to occur by the mechanism fast TiF62-+ H30+FsTiFH-+ H20FsTiFH-+ H20 F5TiH20-+ HF For TiFe2-to hydrolyze in water, an acid solution is required, because the formation of a hydrogen bond and subsequent formation of HF helps to break the Ti-F bond.This result is consistent with the reported acid-cata-lyzed fluorine exchange between SiFe2~s pecies.12 These results are also in agreement with the proposed mechanism for the acid-catalyzed hydrolysis of trans-Co(en)2F2+ where the formation of a hydrogen bond to fluorine weakens the Co-F bond.13In Figure 3 the TiF6-H20" doublet for an initial HF :TiF4 ratio of 1:1 is compared to the doublet for an initial HF:TiF4 ratio of 2:1. Exchange is much faster in the more acidic solution. We suggest that the exchange is due to exchange of both water and fluoride ion. The fluoride ion exchange is facilitated in more acidic solutions by the initial formation of a hydrogen bond, thus lending additional support for the mechanism proposed above.

The preparation of SeI3SbF6 and TeI3SbF6; the X-ray crystal structures of SBr3AsF6, SeI3AsF6, SeI3SbF6, and TeI3SbF6; some considerations of the energetics of the formation of SBr3AsF6 and SeI3AsF6

“…The Raman spectrum and X-ray powder diffraction photograph of the insoluble white solid confirmed the presence of (SbF3),SbF5 (23). The infrared spectrum of the brownblack soluble solid gave peaks at 677 w, 640 sh, 620 vs, 608 sh, 526 sh, and 362 m, cm-consistent with the presence of the SbF6-anion (24 95 mmol), in a two-bulbed vessel equipped with a coarse sintered glass frit. A red-brown solution over a dark precipitate was formed after less than 5 min.…”

“…However, X-ray powder diffraction photography confirmed the presence of the (SbF3)3SbF5 in the reduced product (23). The infrared spectrum of the brown-yellow soluble solid showed peaks at 642 s, sh, 630 vs, and 560 sh, cm-' confirming the presence of the SbF6-anion (24).…”

The characterisation and X-ray crystal structure of pentabromodiselenium hexafluoroarsenate, Se2Br5AsF6; some thermodynamic considerations and the nonexistence of Se2I5AsF6

“…The volatile material was removed by pumping under vacuum. The infrared spectrum of the yellow-orange solid indicated the presence of the AsF6-anion (19 The X-ray crystal structure of Se2Br5AsF6…”

“…The 77Se and I9F nmr spectra, obtained in situ, for a fresh sample of Se2Br5AsF6 prepared by the reaction of Se4(AsF6), and Br2 according to reaction [2] were identical to those described above. The infrared spectrum of solid SezBr5AsF6 also showed the presence of the AsF6-anion (19). Attempts to obtain Raman spectra (exciting line 5145 A) of solid SezBr5AsF6 at room temperature and at -196°C (with and without spinning) were unsuccessful.…”

A New Synthesis of Fluorine Nitrate

“…The nonvolatile white solid residue in the ampoule consisted of 1.0 mmol of CsSbFö that was identified by its Raman spectrum [9].…”