Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-27T10:20:19.290Z Has data issue: false hasContentIssue false
  • English
  • Français

The crystal structure of schairerite and its relationship to sulphohalite

Published online by Cambridge University Press:  05 July 2018

L. Fanfani ,
A. Nunzi ,
P. F. Zanazzi ,
A. R. Zanzari  and
C. Sabelli
L. Fanfani
Affiliation:
Istituto di Mineralogia, Universitàt di Perugia, Perugia, Italy
A. Nunzi
Affiliation:
Istituto di Mineralogia, Universitàt di Perugia, Perugia, Italy
P. F. Zanazzi
Affiliation:
Istituto di Mineralogia, Universitàt di Perugia, Perugia, Italy
A. R. Zanzari
Affiliation:
Istituto di Mineralogia, Universitàt di Perugia, Perugia, Italy
C. Sabelli
Affiliation:
Istituto di Mineralogia, Universitàt di Firenze, Firenze, Italy
Get access Rights & Permissions [Opens in a new window]

Summary

The crystal structure of schairerite from Searles Lake, California, has been determined employing X-ray diffraction data collected on a single-crystal diffractometer. The crystal structure was refined by least-squares methods employing isotropic thermal parameters to a final R index of 0·07 for 2536 independent observed reflections. The cell content is 3[Na21(SO4)7F6Cl]. The space group is P31m with a 12·197 A and c 19·259 Å. Schairerite exhibits a marked sub-cell (a 7·042 Å, the same c axis and P3m1 symmetry), which may be related to the unit cell of sulphohalite when described in a hexagonal lattice.

The crystal structure of schairerite may be considered as consisting of seven sheets of Na+ ions perpendicular to the c axis. These sheets are connected to each other .building up a three-dimensional framework. The Na+ ions in these sheets are arranged in an array built up of hexagons and triangles. Sulphur atoms lie in the sheets at the centres of each hexagon, the halogen atoms lying between the sheets midway between the centres of two triangles. A comparison with sulphohalite shows that the close lattice analogies may be related to a similar atomic arrangement. Apart from the differences in chemical formula (F:C1 ratio 1:1 in sulphohalite), the main difference in the structural framework consists of the unequal number of Na+ sheets (six in sulphohalite) and in the SO42− tetrahedra orientation.

Type
Research Article
Information
Mineralogical Magazine , Volume 40 , Issue 310 , June 1975 , pp. 131 - 139
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1975

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

Brown, (F. H.) and Pabst, (A.), 1971. Amer. Min. 56, 174.Google Scholar
Eoshag, (W. F.), 1931. Ibid., 16, 133.CrossRefGoogle Scholar
Frondel, (C.), 1940. Ibid., 25, 338.Google Scholar
International Tables .for X-ray Crystallography, 1962, 3, 202.Google Scholar
Pabst, (A.), 1934. Zeits. Krist. 89, 514.Google Scholar
Pabst, (A.), Sawyer, (D. L.), and Swrtzer, (G.), 1963. Amer. Min. 48, 485.Google Scholar
Pabst, (A.), and Sharp, (W. N.), 1973. Ibid., 58, 116.Google Scholar
Sakamoto, (Y.), 1968. J. Sci. Hiroshima Univ., Ser. A-II 32, 101.Google Scholar
Takeuchi, (Y.), 1972. Zeits. Krist. 135, 120.CrossRefGoogle Scholar
Watanabe, (T.), 1934. Proc. Imperial Acad. (Japan), 10, 575.CrossRefGoogle Scholar
Wolfe, (C. W.) and Caras, (A.), 1951. Amer. Min. 36, 912.Google Scholar