New symmetry and structure for spinel

@article{Grimes1983NewSA,
  title={New symmetry and structure for spinel},
  author={Norman W. Grimes and P. Thompson and H. F. Kay},
  journal={Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences},
  year={1983},
  volume={386},
  pages={333 - 345}
}
  • N. W. GrimesP. ThompsonH. Kay
  • Published 8 April 1983
  • Materials Science
  • Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
The crystal structure of magnesium aluminate is conventionally described within a symmetry corresponding to the centrosymmetrical space group Fd3m but this has created difficulties for the interpretation of many of its physical properties. Therefore, extensive X-ray diffraction intensity data have been collected from a small spherical synthetic single crystal and used for a structure parameter refinement assuming F4̅3m symmetry as proposed by Grimes (Phil. Mag. 26, 1217‒1226 (1972)), and also… 

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References

SHOWING 1-10 OF 33 REFERENCES

Space group of the spinel structure: A neutron diffraction study of MgAl2O4

It has been suggested that the crystal structure of cubic spinel compounds should be referred to the non-centrosymmetric space group F43m instead of the customary space group Fd3m. The need for the

'Off-centre' ions in compounds with spinel structure

Abstract Experimental evidence from several sources suggests that, contrary to general belief, the crystal structure of cubic spinels is not satisfactorily referred to the space group Fd3m. The

Further discussion on the space group of spinel

Electron-diffraction evidence that spinel has a lower space group than Fd3m is reviewed, and it is reaffirmed that the presence of (200), (420), etc reflections in (001) zone axis diffraction

X-ray diffraction studies of the spinel series Mg(CrxAl2-x)O4 I. Lattice parameters and structure

Eight polycrystalline samples of the spinel series Mg(CrxAl2-x) O4 with 0<or=x<or=2 have been prepared. The lattice parameters have been determined by the centroid method, and the variation with

A neutron‐diffraction study of magnesium aluminium oxide

were established by considering the ratio of the intensities, IhkdIh~, thereby reducing errors arising from absorption effects. The x coordinate was obtained b y considering those reflections hkO for

On the space group of spinel, MgAl2O4

The controversial space-group problem of spinel, MgAl2O4, whether it is Fd3m or F{\bar 4}3m, was studied by electron diffraction. It was confirmed that the appearance of 'forbidden reflections' such

Multiple diffraction in spinel and the space‐group ambiguity

The elimination of the ambiguity in the assignment of a space group for the spinel structure depends upon the detection of very weak `forbidden reflexions' in the presence of substantial multiple

On the specific heat of compounds with spinel structure - II. Zinc ferrite, a paramagnetic compound with magnetic ion occupying the octahedral site

  • N. W. Grimes
  • Materials Science
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The representation of the lattice vibrational component of the specific heat for compounds with cubic spinel structure used in part I is applied to the paramagnetic substance ZnFe2O4 Analysis of the

Antiferroelectricity among compounds with spinel structure

Recent re-evaluation of diffraction data from cubic spinel compounds has suggested that in many cases the crystal structure is properly referred to the noncentrosymmetrical space group F43m. This

A simplified interpretation of the magnetic exchange interactions for chromium chalcogenide spinels

Abstract Following reappraisal of the crystal structure of cubic spinels, it is suggested that the various schemes of exchange interactions which have been proposed by successive authors to explain