Polymorphism and Molecular Dynamics in Beryllium Oxyacetate Be4O(CH3GOO) 6

Abstract

The unusual polymorphism of beryllium oxyacetate, Be4O(CH3COO)6 was investigated by means of pulsed NMR between -196C and the melting point (286.7C) . In the alpha modification of this substance, fast methyl group reorientation takes place, and the spin-spin and spin-lattice relaxation times proved to be insensitive to the presence of the reported second of higher order phase transitions. The transition from a high symmetry cubic phase to a lower symmetry orthorhombic structure on raising the temperature is discussed. No self-diffusion is present up to the melting point. The high temperature gamma phase of beryllium oxyacetate does not seem to be a plastic crystal. Unusual behavior of the spin-lattice relaxation between -20C and -196C was determined.

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Document Details

Document Type
Technical Report
Publication Date
Mar 20, 1972
Accession Number
AD0740840

Entities

People

  • John A. Ripmeester
  • Shmuel Albert

Organizations

  • University of Illinois Urbana–Champaign

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Chemistry
  • Crystal Structure
  • Crystals
  • Diseases And Disorders
  • Energy
  • Frequency
  • Heat Of Activation
  • Low Temperature
  • Melting
  • Melting Point
  • Molecular Dynamics
  • Phase
  • Phase Transformations
  • Relaxation Time
  • Single Crystals
  • Transition Temperature
  • Transitions

Fields of Study

  • Physics

Readers

  • Materials Science and Engineering.
  • Quantum spin resonance or Electron Paramagnetic Resonance spectroscopy.