Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-26T09:32:12.630Z Has data issue: false hasContentIssue false
  • English
  • Français

The Crystal Structure of Stilpnomelane Part I. The Subcell

Published online by Cambridge University Press:  01 January 2024

R. A. Eggleton  and
S. W. Bailey
R. A. Eggleton
Affiliation:
University of Wisconsin, Madison, Wisconsin, USA
S. W. Bailey
Affiliation:
University of Wisconsin, Madison, Wisconsin, USA
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Ferric-iron stilpnomelane is triclinic, space group Pl, a = 21.724 Å, b = 21.724 Å, c = 17.740 Å, α = 124.14°, β = 95.86°, γ = 120,0°, Z = 16. The structure is dominated by a subcell for which as = 1/4a, bs = 1/4b, cs = 1/4c, αs = α, βs = β, γs = γ. The subcell reflections have h-k = 3n, and have a trigonal intensity distribution. The structure was determined from Patterson projections and by trial and error. Three-dimensional refinement by least squares gave an it! factor of 14.4 per cent for 296 reflections.

Stilpnomelane is a layer structure, having five anion and five cation planes parallel to (001). An iron-rich octahedral sheet is flanked by two tetrahedral sheets. The tetra-hedral sheets differ from those found in the common layer silicates in that adjacent tetrahedra point in opposite directions. Each tetrahedral sheet has 1.25 tetrahedra pointing toward the octahedral sheet, and 0.75 tetrahedra pointing away. Detail in the tetrahedral sheet cannot be determined from the subcell reflections only.

Type
Symposium on Structural Aspects of Layer Silicate
Information
Clays and Clay Minerals (National Conference on Clays and Clay Minerals) , Volume 13 , February 1964 , pp. 49 - 63
Copyright
Copyright © The Clay Minerals Society 1964

References

Ayres, Y. L. (1940) Mineral notes from the Michigan iron country, Am. Mineralogist 25, 432.Google Scholar
Brown, B. E., and Bailey, S. W. (1963) Chlorite polytypism, II. Crystal structure of a one-layer Cr-chlorite, Am. Mineralogist 48, 42–61.Google Scholar
Burnham, C. W., and Buerger, M. J. 1961. Refinement of the crystal of andalusite, Z. Krist. 115, 268–70. Fankuchen, I. Cited by Hutton, S. O. (1938) Glocker. (1828) Z. S. F. Min., Jan.CrossRefGoogle Scholar
Gruner, J. W. (1937) Composition and structure of stilpnomelane, Am. Mineralogist 22, 912–25.Google Scholar
Gruner, J. W. (1944) The structure of stilpnomelane re-examined, Am. Mineralogist 29, 291–8.Google Scholar
Howells, E. R., Phillips, D. C., and Rogers, D. (1950) The probability distribution of X-ray intensities, II, Experimental investigation and the X-ray detection of centers of symmetry, Acta Cryst. 3, 210–14.CrossRefGoogle Scholar
Hutton, S. O. (1938) The stilpnomelane group of minerals, Mineral. Mag. 25, 172–206.Google Scholar
Hutton, S. O. (1944) Additional optical and chemical data on the stilpnomelane group of minerals, Am. Mineralogist 30, 714–8.Google Scholar
Hutton, S. O. (1956) Further data on the stilpnomelane group of minerals, Am. Mineralogist 41, 608–15.Google Scholar
Raynor, E. O. (1961) The mineralogy and genesis of iron-rich copper ores of the Cobar province, New South Wales, Geol. Survey New South Wales. Unpublished Report.Google Scholar
Swanson, H. E., Gilfrich, N. T., and Ugrinic, G. M. (1955) Standard X-ray diffraction powder patterns, vol. 5, Nat. Bur. Standards Circ. 539.Google Scholar
Waser, J. (1951) The Lorentz factor for the Buerger Precession Camera, Rev. Sci. Instr. 22, 563–8.Google Scholar