Refined ettringite (Ca6Al2(SO4)3(OH)12x26H2O) structure for quantitative X-Ray diffraction analysis

Journal article
(Original article)


Publication Details

Author(s): Götz-Neunhoeffer F, Neubauer J
Journal: Powder Diffraction
Publication year: 2006
Volume: 21
Journal issue: 1
Pages range: 4-11
ISSN: 0885-7156
Language: English


Abstract


A revised structure model of ettringite is presented, in order to provide quantitative X-ray diffraction (QXRD) of this mineral in cement pastes. The model is derived from two different existing structure models, both of which are suitable for restricted use but are inferior to the refined ettringite structure presented. In the first published ettringite structure proposed by Moore and Taylor [Acta Crystallogr. B 26, 386-393 (1970)], none of the 128 positions for H are given in the unit cell, which results in reduced scattering power for use of this model for quantification purposes. For the precise quantification of ettringite in samples together with anhydrous phases, the scattering factors of all atoms including the H positions are indispensable. The revised structure model is based on the data of Moore and Taylor, supplemented by the H positions determined by Berliner (Material Science of Concrete Special Volume, The Sydney Diamond Symposium, American Ceramic, Society, 1998, pp. 127-141) on the basis of a neutron diffraction structural investigation of deuterated ettringite at 20 K. Berliner's (Material Science of Concrete Special Volume, The Sydney Diamond Symposium, American Ceramic Society, 1998, pp. 127-141) thermal parameter should not, however, be used, since a normal application is at room temperature. In order further to improve the structure model of ettringite, Rietveld refinement with the rigid body approach for OH and H2 O molecules and SO4 tetrahedra was employed. The refined and improved ettringite structure model was tested for quantitative phase analysis by the determination of actual ettringite contents in mixtures with an internal standard. Synthesized and orientation-free prepared ettringite powders were investigated by X-ray powder diffraction analysis and quantified in four different blends with zircon. The quantification results with the new structure model demonstrate the superior quality of the revised ettringite structure. © 2006 International Centre for Diffraction Data.


FAU Authors / FAU Editors

Götz-Neunhoeffer, Friedlinde Prof. Dr.
Lehrstuhl für Mineralogie
Neubauer, Jürgen apl. Prof. Dr.
Lehrstuhl für Mineralogie


How to cite

APA:
Götz-Neunhoeffer, F., & Neubauer, J. (2006). Refined ettringite (Ca6Al2(SO4)3(OH)12x26H2O) structure for quantitative X-Ray diffraction analysis. Powder Diffraction, 21(1), 4-11. https://dx.doi.org/10.1154/1.2146207

MLA:
Götz-Neunhoeffer, Friedlinde, and Jürgen Neubauer. "Refined ettringite (Ca6Al2(SO4)3(OH)12x26H2O) structure for quantitative X-Ray diffraction analysis." Powder Diffraction 21.1 (2006): 4-11.

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Last updated on 2018-20-12 at 16:48