AN NMR STUDY OF THE ALKALI HEXAFLUOROPHOSPHATES' DYNAMIC STRUCTURE

Abstract

The fluorine nuclear magnetic resonance spectra of the sodium, potassium, rubidium and cesium hexafluorophosphates were studied between 77 and 400 K. In each of the salts the PF6(-) ions are reorienting about the octahedral axes at random or nearly so for temperatures of 200 K and above. The broadening of the fluorine resonance in these solids at lower temperatures indicates that the ease with which the PF6(-) groups reorient in creases with increasing size of the alkali metal cation, so that for CsPF6 the fluorine resonance is still narrow at 77 K. A quantitative study of the potential barriers to PF6(-) group re orientation was discouraged by the discovery that the fluorine line shapes and widths are remark ably sensitive to the physical state and in the case of RbPF6 the thermal history of the sample. Fluorine line shape studies reported previously for solid CF4 are reinterpreted in terms of a similar two-phase cooperative process for the freezing out of the CF4 reorientations.

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Document Details

Document Type
Technical Report
Publication Date
Mar 16, 1963
Accession Number
AD0403410

Entities

People

  • Gerald R. Miller
  • Herbert S. Gutowsky

Organizations

  • University of Illinois Urbana–Champaign

Tags

Communities of Interest

  • Advanced Electronics
  • Counter WMD
  • Energy and Power Technologies
  • Weapons Technologies

DTIC Thesaurus Topics

  • Alkali Metals
  • Chemical Shifts
  • Chemistry
  • Crystal Lattices
  • Crystal Structure
  • Crystals
  • Cubic Lattices
  • Equations
  • Frequency
  • Low Temperature
  • Magnetic Fields
  • Magnetic Resonance
  • Military Research
  • New York
  • Nuclear Magnetic Resonance
  • Nuclei
  • Phase Transformations

Readers

  • Geochemistry
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.