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An X-ray study of the crystal-structure of antigorite (With Plate V)

Published online by Cambridge University Press:  14 March 2018

Endel Aruja
Endel Aruja*
Affiliation:
King's College, Newcastle upon TyneUniversity of Durham). (Now at Adam Hilger Ltd., LondonN.W.1.)
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Extract

Antigorite is a lamellar variety of serpentine, and is supposed to be a dimorphous form of chrysotile, which is finely fibrous. Its chemical composition is approximately H4Mg3Si2O9, which is taken as the basis of calculations here.

This study was undertaken primarily because it was hoped that knowledge of the structure of antigorite would throw some light on that of chrysotile. Certain similarities between the two structures have been established, namely in the c(7·3kX or 14·6kX), and b(9·2kX) directions. There are two main differences, however. Firstly, imperfections which cause line broadening in the X-ray pattern of chrysotile, are absent in antigorite (apart from certain ‘streaks’). Secondly, the a(43·4kX) axis of antigorite is approximately eight times longer than the corresponding axis in chrysotile. A complete determination of the structure has not been achieved, but the X-ray pattern has been described, and some suggestions made as to the explanation of the peculiarities observed. A further study of the outstanding questions is in progress.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 27 , Issue 188 , March 1945 , pp. 65 - 74
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1945

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References

page 65 note 1 lkX = 1000 X-units, as defined by Siegbahn. IkX = 1·00203x10−8 cm., according to the up-to-date value of Avogadro's number, 6·0228x10−23 per mole. Cf. H. Lipson and D. P. Riley, Nature, 1943, vol. 151, p. 250, and A. J. C. Wilson, ibid., p. 562. [M.A. 9–39.]

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