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The transformation manganite → pyrolusite

Published online by Cambridge University Press:  05 July 2018

P. E. Champness
P. E. Champness*
Affiliation:
Department of Geology, University of Manchester
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Summary

During the transformation of manganite to pyrolusite the b-axis must contract about 15 %. There is evidence that the shrinkage takes place partly by contraction of the whole crystal, but electron-microscope investigations of natural pyrolusites and of manganite oxidized in the laboratory show that the reaction also involves the formation of lamellar pores about 85 Å apart, parallel to (010) of the original manganite. Thus, although pyrolusite is tetragonal, the a- and b-axes are not microscopically identical, a fact which could explain why, when natural pyrolusite is treated hydrothermally at 200 and 300 °C and 1000 bars, only one orientation of manganite is formed (Dent Glasser and Smith, 1968). The pores and the accompanying distortion of the structure act as a ‘memory’ of the parent phase.

Type
Research Article
Information
Mineralogical Magazine , Volume 38 , Issue 294 , June 1971 , pp. 245 - 248
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2013

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Footnotes

1

This paper was read at the Mineralogical Society meeting ‘Order-Disorder Effects in Minerals’ held in Aberdeen on 18–19 September 1969.

References

Buerger, (M.J.), 1936. Zeits. Krist. 95, 163.Google Scholar
Dasgupta, (D.R.), 1965. Min. Mag. 35, 131.Google Scholar
Davis, (R.J.), 1967. Ibid. 36, 274.Google Scholar
Dent Glasser, (L. S.) and Smith, (I.B.), 1968. Ibid. 36, 976.Google Scholar
Garrido, (M.J.), 1935. Bull. Soc. franc. Min. 58, 224.Google Scholar
Kitaigorodskiy, (A.I.), Mnyukh, (Yu. V.), and Asadov, (Yu. G.), 1965. Journ. Phys. Chem. Solids, 26, 463.CrossRefGoogle Scholar
Strunz, (H.), 1943. Naturwiss. 31, 89.CrossRefGoogle Scholar