Hostname: page-component-8448b6f56d-jr42d Total loading time: 0 Render date: 2024-04-23T21:23:50.141Z Has data issue: false hasContentIssue false
  • English
  • Français

Further study of the cation ordering in phengite 3T by neutron powder diffraction

Published online by Cambridge University Press:  25 June 2018

A. Pavese ,
G. Ferraris ,
V. Pischedda  and
P. Radaelli
A. Pavese*
Affiliation:
Dipartimento di Scienze della Terra, Università di Milano, Via Botticelli 23, I-20133 Milano, Italy National Research Council, CNR, Centro di Studio per la Geodinamica Alpina e Quaternaria, Via Mangiagalli 34, 20133 Milano, Italy
G. Ferraris
Affiliation:
Dipartimento di Scienze Mineralogiche e Petrologiche, Università di Torino, Via Valperga Caluso 35, I-10125 Torino, Italy
V. Pischedda
Affiliation:
Dipartimento di Scienze Mineralogiche e Petrologiche, Università di Torino, Via Valperga Caluso 35, I-10125 Torino, Italy
P. Radaelli
Affiliation:
ILL Facility, Institut Laue-Langevin, 38042 Grenoble, France
*
*E-mail: pavese@p8000.terra.unimi.it
Get access Rights & Permissions [Opens in a new window]

Abstract

Phengite 3T (Dora-Maira massif, Italian western Alps), with chemical composition K0.96Na0.01Al1.44Mg0.56(Si3.59 Al0.41)O10(OH)2 has been investigated using powder neutron diffraction, at the ILL (Institut Laue-Langevin) Facility, on the D2B diffractometer. Data sets were collected at 293 and 873 K, and the present results are compared with those obtained previously using the time-of-flight (TOF) technique, on the same compound. In the octahedral sheet, Al tends to order into the M2 site, in accordance with the measurements mentioned above, whereas the Al/Si tetrahedral ordering we observe (i.e. Si fully into T1 site) is at variance with that determined previously. These discrepancies are ascribed to the presence of talc impurities in the sample used previously (∼6 wt.%), which affected the results obtained.

Keywords

neutron powder diffractionphengite 3TDora-Mairatetrahedral and octahedral orderRietveld refinement
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 1 , February 2000 , pp. 11 - 18
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

†

Present address: ISIS Facility, Rutherford Appleton Laboratory, Chilton-Didcot, Oxon OX11 0QX, UK

References

Amisano-Canesi, A., Chiari, G., Ferraris, G., Ivaldi, G. and Soboleva, V.S. (1994) Muscovite and phengite 3T: crystal structure and conditions of formation. Eur. J. Mineral., 6, 489–96.CrossRefGoogle Scholar
Dollase, W.A. (1986) Correction of intensities for preferred orientation in powder diffractometry: application of the March model. J. Appl. Cryst., 19, 267–72.CrossRefGoogle Scholar
Ferraris, C., Lanfranco, A.M. and Hiltunen, R. (1997) Polytypism and non periodic interstratifications in some alpine micas: HRTEM and multiphase carbon detector data. MODUL 97-Modular Aspects of Minerals, Abstracts. 1st EMU School and Symposium. Budapest, Hungary, p. 19.Google Scholar
Ferraris, G., Ivaldi, G., Nespolo, M. and Takeda, H. (1995) On the stability of dioctahedral micas. Terra Abstr. (Suppl. No. 1, Terr. Nova), 7, 289.Google Scholar
Hazen, R.M. and Burnham, C.W. (1973) The crystal structure of one layer phlogopite and annite. Amer. Mineral., 58, 889–900.Google Scholar
Howard, C.J. (1982) The approximation of asymmetric neutron powder diffraction peaks by sums of gaussians. J. Appl. Crystallogr., 15, 615–20.CrossRefGoogle Scholar
Larson, A.C. and Von Dreele, R.B. (1986) GSAS: General Software Analysis System Manual. Los Alamos National Laboratory Report. LAUR: 86–87.Google Scholar
Nespolo, M., Takeda, H. and Ferraris, G. (1997) Crystallography of mica polytypes. Pp. 81–118 in: Modular Aspects of Minerals (Merlino, S., editor). EMU Notes in Mineralogy, 1.CrossRefGoogle Scholar
Pavese, A., Ferraris, G., Prencipe, M. and Ibberson, R. (1997) Cation site ordering in phengite 3T from the Dora Maira massif (western Alps) a variable-temperature neutron powder diffraction study. Eur. J. Mineral., 9, 1183–90.CrossRefGoogle Scholar
Pavese, A., Ferraris, G., Pischedda, V. and Ibberson, R. (1999) Tetrahedral order upon heating in phengite 2M 1, from powder neutron diffraction. Eur. J. Mineral., 11, 309–20.CrossRefGoogle Scholar
Perdikatsis, B. and Burzlaff, H. (1981) Strukturverfeinerung am Talc Mg2 [(OH)2Si4O10]. Zeits. Kristallogr., 156, 177–86.Google Scholar
Vieillard, Ph. (1995) How do uncertainties of structure refinements influence the accuracy of the prediction of enthalpy of formation? Examples on muscovite and natrolite. Phys. Chem. Min., 22, 428–36.CrossRefGoogle Scholar
Wentzcovitch, R.M. and Stixrude, L. (1997) Crystal chemistry of forsterite: a first principles study. Amer. Mineral., 82, 663–71.CrossRefGoogle Scholar
Yamanaka, T. and Takeuchi, Y. (1983) Order-disorder transition in MgAl2O4 spinel at high temperature up to 1700°C. Zeits. Kristallogr., 165, 65–78.CrossRefGoogle Scholar