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Difference between revisions of "Aristotype"

From Online Dictionary of Crystallography

(Tidied translations and added German and Spanish (U. Mueller))
 
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An arisotype in crystallography is a high-symmetry structure type that can be viewed as an idealized version of a lower symmetry structure.  I believe Helen Megaw introduced the term in relation to perovskites which it is where it is still mostly used, the cubic perovskite structure (which is adopted at most half a dozen compounds) is regarded as the aristotype for the vast array of other lower-symmetry perovskites.
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<font color="blue">Aristotype</font> (''Fr''). <font color="red">Aristotyp</font> (''Ge''). <font color="black">Aristotipo</font> (''It''). <font color="purple">アリストタイプ</font> (''Ja''). <font color="green">Aristotipo</font> (''Sp'').
Orig., a printing-out process using paper coated with silver chloride in gelatin; now, any such process using silver salts in either collodion or gelatin; also, a print so made.
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== Definition ==
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An aristotype is a high-symmetry structure type that can be viewed as an idealized version of a lower-symmetry structure.  It was introduced by Helen Megaw in relation to perovskites, where it is still mostly used. The cubic perovskite structure (which is adopted at most by half a dozen compounds) is regarded as the aristotype for the vast array of other lower-symmetry perovskites. The lower-symmetry structure is called '''hettotype'''.
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After Buerger, aristotypes are also known as '''basic structures''' and hettotypes as '''derivative structures'''.  
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Originally, an aristotype is a printing-out process using paper coated with silver chloride in gelatin; now, any such process using silver salts in either collodion or gelatin; also, a print so made.
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== References ==
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*Buerger, M. J. (1947). ''J. Chem. Phys.'' '''15''', 1-16. ''Derivative Crystal Structures''.
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*Megaw, H. (1973). ''Crystal Structures'', London: W. B. Saunders,  pp. 216, 282.
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[[Category:Fundamental crystallography]]

Latest revision as of 18:02, 8 November 2017

Aristotype (Fr). Aristotyp (Ge). Aristotipo (It). アリストタイプ (Ja). Aristotipo (Sp).

Definition

An aristotype is a high-symmetry structure type that can be viewed as an idealized version of a lower-symmetry structure. It was introduced by Helen Megaw in relation to perovskites, where it is still mostly used. The cubic perovskite structure (which is adopted at most by half a dozen compounds) is regarded as the aristotype for the vast array of other lower-symmetry perovskites. The lower-symmetry structure is called hettotype.

After Buerger, aristotypes are also known as basic structures and hettotypes as derivative structures.

Originally, an aristotype is a printing-out process using paper coated with silver chloride in gelatin; now, any such process using silver salts in either collodion or gelatin; also, a print so made.

References

  • Buerger, M. J. (1947). J. Chem. Phys. 15, 1-16. Derivative Crystal Structures.
  • Megaw, H. (1973). Crystal Structures, London: W. B. Saunders, pp. 216, 282.