Clays and Clay Minerals

, Volume 44, Issue 6, pp 744–748 | Cite as

Crystal Structure Modeling of a Highly Disordered Potassium Birnessite

  • Kerry L. Holland
  • Jeffrey R. Walker


The structure of a highly disordered synthetic birnessite was studied by comparing powder X-ray diffraction (XRD) data with calculated patterns generated by BIRNDIF and WILDFIRE© in an attempt to describe the nature of disorder and to estimate the size of the coherent diffracting domains. The material has a turbostratic stacking sequence and coherent diffracting domains that are 25 to 30 Å on a side in the ab plane (N1 = 5 unit cells, N2 = 10 unit cells) and which average 2.5 unit cells thick parallel to c. Turbostratic stacking probably results because there are few constraints on the relationship between adjacent layers.

Key Words

Birnessite Crystal Structure Modeling Turbostratic Stacking 


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Copyright information

© The Clay Minerals Society 1996

Authors and Affiliations

  • Kerry L. Holland
    • 1
  • Jeffrey R. Walker
    • 1
  1. 1.Department of Geology and GeographyVassar CollegePoughkeepsieUSA

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