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The low-temperature behaviour of analcime. 1: high-resolution neutron powder diffraction

Published online by Cambridge University Press:  05 July 2018

C. M. B. Line
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
M. T. Dove
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
K. S. Knight
Affiliation:
ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK
B. Winkler
Affiliation:
Mineralogisch-Petrographisches Institut der Christian Albrechts, Universität, Olshausenstr. 40, D-24098 Kiel, Germany

Abstract

The structure of a synthetic sample of analcime has been determined as a function of temperature between 30–300 K by high-resolution neutron powder diffraction. Although there are some reports of samples of analcime having non-cubic structures, the sample in our experiments remained cubic (space group la3d), and hence disordered, down to low temperatures. The absence of phase transitions involving ordering of the orientations of the water molecules, ordering of the sodium positions, or a displacive instability as in leucite and related materials, is discussed. We speculate that part of the reason for the absence of ordering of the water molecules or sodium cations is associated with the Al/Si disorder, which cannot order at low temperatures. We also discuss the likely distribution of the orientations of the water molecules at low temperatures, and propose that the water diads lie close to any of the crystal diads with the H-H Vectors lying close to the triads.

Type
Mineralogy
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1996

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Footnotes

*

Present address: Institut Laue Langevin, BP 156, 38042 Grenoble Cedex 9, France

References

Bee, M. (1988) Quasielastic Neutron Scattering.(Adam Hilger, Bristol).Google Scholar
David, W.I.F., Ibberson, R.M. and Matthewmann, J.C. (1992) Rutherford Appleton report RAL-92-032. Dove, M.T., Cool, T., Palmer, D.C., Putnis, A., Salje, E.K.H. and Winkler, B. (1993) On the role of Al/Si ordering in the cubic-tetragonal phase transition in leucite. Amer. Mineral, 78, 486–92.Google Scholar
Dove, M.T., Heine, V. and Hammonds, K.D. (1995) Rigid unit modes in framework silicates. Mineral Mag., 59, 629–39.CrossRefGoogle Scholar
Dove, M.T. and Heine, V. (1996) The use of Monte Carlo methods to determine the distribution of A1 and Si cations in framework aluminosilicates from 29Si MAS-NMR data. Amer. Mineral, 81, 3944.CrossRefGoogle Scholar
Dove, M.T., Thayaparam, S., Heine, V. and Hammonds, K.D. (1996) The phenomenon of low Al/Si ordering temperatures in aluminosilicate framework structures. Amer. Mineral., 81, 349–62.CrossRefGoogle Scholar
Ferraris, G., Jones, D.W. and Yerkess, J. (1972) A neutron diffraction study of the crystal structure of analcime, NaAlSi2O6 H2O. Zeit. Kristallogr., 135, 240–52.CrossRefGoogle Scholar
Hammonds, K.D., Dove, M.T., Giddy, A.P., Heine, V. and Winkler, B. (1995) Rigid unit phonon modes and structural phase transitions in framework silicates. Amer. Mineral(in press).CrossRefGoogle Scholar
Hobbs, P.V. (1974) Ice Physics.(Clarendon Press, Oxford).Google Scholar
Line, C.M.B. Winkler, B. and Dove, M.T. (1994) Quasielastic incoherent neutron scattering study of the rotational dynamics of the water molecules in analcime. Phys. Chem. Mineral., 21, 451–9.CrossRefGoogle Scholar
Line, C.M.B. (1995) The behaviour of water in analcime.PhD thesis, University of Cambridge.Google Scholar
Line, C.M.B., Putnis, A., Putnis, C. and Giampaolo, C. (1995) The dehydration kinetics and microtexture of analcime from two parageneses. Amer. Mineral., 80, 268–79.CrossRefGoogle Scholar
Line, C.M.B., Dove, M.T. and Swainson, I.P. (1996) The dehydration of analcime studied using both coherent and incoherent neutron scattering. Amer. Mineral.(submitted).Google Scholar
Mazzi, F. and Galli, E. (1978) Is each analcime different? Amer. Mineral., 63, 448–60.Google Scholar
Palmer, D.C., Dove, M.T., Ibberson, R.M. and Powell, B.M. (1996) Structural behavior, crystal chemistry and phase transitions in substituted leucites. Amer. Mineral,(in press).Google Scholar
Pechar, F. (1988) The crystal structure of natural monoclinic analcime (NaAlSi2O6'H2O). Zeit. Kristallogr., 184, 63–9.CrossRefGoogle Scholar
Phillips, B.L. and Kirkpatrick, R.J. (1994) Short-range Si-Al order in leucite: determination of the configurational entropy from 27A1 and variable-temperature 29Si NMR spectroscopy of leucite, its Cs- and Rb-exchanged derivatives, and analcime. Amer. Mineral., 79, 1025–31.Google Scholar
Sears, V.F. (1992) Neutron scattering lengths and crosssections. Nutrons, News, 3, 2637.CrossRefGoogle Scholar
Soper, A.K. (1984) The structure of liquid water at room temperature. Chem. Phys., 88, 187–97.CrossRefGoogle Scholar
Winkler, B., Coddens, G. and Hennion, B. (1994) Movement of channel H20 in cordierite observed with quasi-elastic neutron scattering. Amer. Mineral., 79, 801–8.Google Scholar
Winkler, B. and Hennion, B. (1994) Low temperature dynamics of molecular H2O in bassanite, gypsum and cordierite investigated by high resolution incoherent inelastic neutron scattering. Phys. Chem. Miner., 21, 539–45.CrossRefGoogle Scholar