# 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}
}
• 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…

## Tables from this paper

### Does magnetite lack a centre of symmetry

• Physics
• 1988
Doubts concerning the conventionally assumed centrosymmetry of the cubic crystal structure of spinel ferrites, including magnetite, have existed for many years, chiefly because dielectric constants

### Crystal chemistry of a highly disordered Mg-Al natural spinel

• Chemistry
• 1997
SummaryA Mg-Al spinel from a xenolith found in the Sacrofano volcanic area (Latium, Italy) was investigated by X-ray single crystal diffraction and electron microprobe. Its main structural parameters

### Cation ordering and structural variations with temperature in MgAl2O4 spinel: An X-ray single-crystal study

• Materials Science
• 2000
Abstract The equilibrium distribution of Mg and Al between the tetrahedral and octahedral sites of a flux grown, stoichiometric MgAl2O4 spinel was investigated between 600 and 1100 °C by

### Cation distribution in natural Zn-aluminate spinels

• Materials Science
• 1998
Abstract The intracrystalline cation distributions in fourteen natural Zn-aluminate spinels were determined by means of X-ray single-crystal structural refinement, supported for some samples by

### Crystal Structures and Cation Distributions in Simple Spinels from Powder XRD Structural Refinements : MgCr 204 , ZnCr 204 , Fe 304 and the Temperature Dependence of the Cation Distribution in ZnAl 204

• Materials Science
• 2004
The crystal structure and cation distributions in the spinels MgCr204, ZnCr20~, Fe30~ and a suite of ZnA1204 samples annealed at 900 to 1400 ~ C and then rapidly quenched, have been determined by

### Ab Initio Thermodynamic and Structural Studies of Cationic Disordered MgAl2O4 Spinel

• Chemistry, Materials Science
• 2005
Structural and thermodynamic properties of disordered MgAl2O4 spinel are calculated by DFT with plane-wave basis set and pseudopotentials. Several configurations are considered to average each

### Inversion in Mg1-xNixAl2O4 Spinel: New Insight into Local Structure.

• Geology
Journal of the American Chemical Society
• 2017
Based on neutron total scattering experiments, it is determined that the local structure of Mg1-xNixAl2O4 spinel cannot be understood as simply being due to cation disorder, rather, cation inversion creates a local tetragonal symmetry that extends over sub-nanometer domains.

### Structure of Spinel

• Materials Science
• 2000
This paper reviews the crystal structure of compounds with the general formula AB 2 X 4 , which crystallize with the same atomic structure as the mineral spinel, MgAl 2 O 4 . Three degrees of freedom

## References

SHOWING 1-10 OF 33 REFERENCES

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

• Geology
• 1976
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

• Geology
• 1975
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

• Materials Science
• 1970
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

• Chemistry
• 1980
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

• Geology
• 1977
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
Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences
• 1974
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

• Materials Science
• 1977
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