Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-23T12:08:34.053Z Has data issue: false hasContentIssue false
  • English
  • Français

Fe-Mn cation ordering in fayalite–tephroite (FexMn1−x)2SiO4 olivines: a neutron diffraction study

Published online by Cambridge University Press:  05 July 2018

S. A. T. Redfern ,
K. S. Knight ,
C. M. B. Henderson  and
B. J. Wood
S. A. T. Redfern
Affiliation:
Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
K. S. Knight
Affiliation:
ISIS, Rutherford Appleton Laboratory, Oxon, OX11 0QX, UK
C. M. B. Henderson
Affiliation:
Department of Earth Sciences, University of Manchester, Oxford Road, Manchester, MI3 9PL, UK
B. J. Wood
Affiliation:
Department of Geology, University of Bristol, Queens Road, Bristol, BS8 1RJ, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

Time-of-flight neutron powder diffraction has been employed to determine precise occupancies of the M1 and M2 metal cation sites in synthetic olivines of compositions (Fe0.3Mn0.7)2SiO4, (Fe0.5Mn0.5)2−SiO4, and (Fe0.7Mn0.3)2SiO4. The distribution coefficient for Fe-Mn exchange in these samples has values of 4.864, 3.976, and 4.078, reflecting the preference of Mn2+ for the M2 site, over Fe2+. These results, and the behaviour of the difference in mean bond lengths of the two sites, indicate that, while showing a tendency towards ordering, the composition-dependence of the solid solution is near ideal.

Keywords

olivinesnetron powder diffractioncation sitesbond length
Type
Research Article
Information
Mineralogical Magazine , Volume 62 , Issue 5 , October 1998 , pp. 607 - 615
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1998

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.)

References

Annersten, H., Adetunji, J. and Filippidis, A. (1984) Cation ordering in Fe-Mn silicate olivines. Amer. Mineral., 69, 1110–5.Google Scholar
Artioli, G., Rinaldi, R., Wilson, C.C. and Zanazzi, P.F. (1995) High-temperature cation partitioning in olivine: In situ single-crystal neutron diffraction study. Amer. Mineral., 80, 197–200.CrossRefGoogle Scholar
Ballet, O., Fuess, H. and Fritzsche, T. (1987) Magnetic structure and cation distribution in (Fe,Mn)2SiO4 (olivine) by neutron diffraction. Phys. Chem. Minerals, 15, 54–8.CrossRefGoogle Scholar
Brown, G.E. (1982) Olivine and silicate spinels. In Orthosilicates (Ribbe, P.H., ed.). Reviews in Mineralogy, 5, 2nd edition, p. 275–381. Mineralogical Society of America, Washington, D.C.Google Scholar
Francis, C. A. and Ribbe, P.H. (1980) The forsterite– tephroite series: 1. Crystal structure refinements. Amer. Mineral., 65, 1263–9.Google Scholar
Fujino, K., Sasaki, S., Takéuchi, Y. and Sadanaga, R. (1981) X-ray determination of electron distributions in forsterite, fayalite and tephroite. Acta. Crystallogr., B37, 513–8.CrossRefGoogle Scholar
Ghose, S. (1962) The nature of Mg2+-Fe2+ distribution in some ferromagnesian silicate minerals. Amer. Mineral., 47, 388–94.Google Scholar
Henderson, C.M.B., Artioli, G., Knight, K.R., Redfern, S.A.T., Rinaldi, R. and Wood, B.J. (1996 a) Temperature and composition dependenc of Fe-Mg ordering in olivines. ISIS 1996 Annual Report (CLRC), A18.Google Scholar
Henderson, C.M.B., Knight, K.S., Redfern, S.A.T. and Wood, B.J. (1996 b) High-temperature study of octahedral cation exchange in olivine by neutron powder diffraction. Science, 271, 1713–5.CrossRefGoogle Scholar
Hull, S., Smith, R.I., David, W.I.F., Hannon, A.C., Mayers, J. and Cywinski, R. (1992) The POLARIS powder diffractometer at ISIS. Physica B, 180, 1000–2.CrossRefGoogle Scholar
Lumpkin, G.R. and Ribbe, P.H. (1983) Composition, order-disorder and lattice parameters of olivines: relationships in silicate, germanate, beryllate, phosphate and borate olivines. Amer. Mineral., 68, 164–76.Google Scholar
Miller, M.L. and Ribbe, P.H. (1985) Methods for determination of composition and intracrystalline cation distribution in Fe-Mn and Fe-Ni silicate olivines. Amer. Mineral., 70, 723–8.Google Scholar
Redfern, S.A.T., Henderson, C.M.B., Wood, B.J., Harrison, R.J. and Knight, K S. (1996) Determination of olivine cooling rates from metalcation ordering. Nature, 381, 407–9.CrossRefGoogle Scholar
Redfern, S.A.T., Henderson, C.M.B., Knight, K.S. and Wood, B.J. (1997) High-temperature order-disorder in (Fe0.5Mn0.5)2SiO4 and (Mg0.5Mn0.5)2SiO4 olivines: an in situ neutron diffraction study. Eur. J. Mineral., 9, 287–300.CrossRefGoogle Scholar
Rietveld, H.M. (1969) A profile refinement methods for nuclear and magnetic structures. J. Appl. Crystallogr., 2, 65-71.CrossRefGoogle Scholar
Rinaldi, R. and Wilson, C.C. (1996) Crystal dynamics by neutron time-of-flight Laue diffraction in olivine up to 1573 K using single frame methods. Solid State Comm., 97, 395–400.CrossRefGoogle Scholar
Sears, V.F. (1992) Neutron scattering lengths and cross sections. Neutron News, 3, 26–37.CrossRefGoogle Scholar