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The wulfenite—stolzite series: centric or acentric structures?

Published online by Cambridge University Press:  05 July 2018

L. Secco ,
F. Nestola  and
A. Dal Negro
L. Secco*
Affiliation:
Dipartimento di Geoscienze, Università di Padova, Via Giotto 1, I-35137, Padova, Italy
F. Nestola
Affiliation:
Dipartimento di Geoscienze, Università di Padova, Via Giotto 1, I-35137, Padova, Italy
A. Dal Negro
Affiliation:
Dipartimento di Geoscienze, Università di Padova, Via Giotto 1, I-35137, Padova, Italy
*
*E-mail: [email protected]
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Abstract

Three natural crystals of the wulfenite (PbMoO4)—stolzite (PbWO4) series were investigated by single-crystal X-ray diffraction. The results indicate that the symmetry is I41/a from nearly pure wulfenite to intermediate compositions, in contrast to previous work which claimed a symmetry change to 74 symmetry (acentric) for intermediate compositions compared with I41/a (centric space group) for the end-members. The results reported here show that the reflections violating I41/a symmetry observed in this work and in a previous study are related primarily to λ/2 effects, even if Renninger effects are not excluded. Consequently, we find that the I41/a symmetry is retained throughout the wulfenite— stolzite.

Keywords

wulfenitestolzitesingle-crystalX-ray diffraction
Type
Research Article
Information
Mineralogical Magazine , Volume 72 , Issue 4 , August 2008 , pp. 987 - 990
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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