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The Setting Behaviour of α- and β-CaSO4 · 0,5 H2O as a Function of Crystal Structure and Morphology

2002; Wiley; Volume: 37; Issue: 10 Linguagem: Inglês

10.1002/1521-4079(200210)37

1521-4079

S. Follner, Albrecht Wolter, Andrea Preusser, Sylvio Indris, C. Silber, H. Follner,

X-ray Diffraction in Crystallography

Crystal Research and TechnologyVolume 37, Issue 10 p. 1075-1087 Original Paper The Setting Behaviour of α- and β-CaSO4 · 0,5 H2O as a Function of Crystal Structure and Morphology S. Follner, S. Follner [email protected] Institut für Nichtmetallische Werkstoffe der TU Clausthal, GermanySearch for more papers by this authorA. Wolter, A. Wolter Institut für Nichtmetallische Werkstoffe der TU Clausthal, GermanySearch for more papers by this authorA. Preusser, A. Preusser Geowissenschaftliches Zentrum, Abtlg. Kristallographie, der Georg-August-Universität GöttingenSearch for more papers by this authorS. Indris, S. Indris Institut für Physikalische Chemie und Elektrochemie der Universität Hannover, GermanySearch for more papers by this authorC. Silber, C. Silber Institut für Mineralogie und Mineralische Rohstoffe der TU Clausthal, GermanySearch for more papers by this authorH. Follner, H. Follner Institut für Mineralogie und Mineralische Rohstoffe der TU Clausthal, GermanySearch for more papers by this author S. Follner, S. Follner [email protected] Institut für Nichtmetallische Werkstoffe der TU Clausthal, GermanySearch for more papers by this authorA. Wolter, A. Wolter Institut für Nichtmetallische Werkstoffe der TU Clausthal, GermanySearch for more papers by this authorA. Preusser, A. Preusser Geowissenschaftliches Zentrum, Abtlg. Kristallographie, der Georg-August-Universität GöttingenSearch for more papers by this authorS. Indris, S. Indris Institut für Physikalische Chemie und Elektrochemie der Universität Hannover, GermanySearch for more papers by this authorC. Silber, C. Silber Institut für Mineralogie und Mineralische Rohstoffe der TU Clausthal, GermanySearch for more papers by this authorH. Follner, H. Follner Institut für Mineralogie und Mineralische Rohstoffe der TU Clausthal, GermanySearch for more papers by this author First published: 30 September 2002 https://doi.org/10.1002/1521-4079(200210)37:10 3.0.CO;2-XCitations: 41AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Abstract Calcium sulphate subhydrates (CaSO4 · x H2O, 0 < x ≤ 0.8) have a honeycomb-shaped channel structure. The symmetry is either trigonal or a slight deviation thereof. Due to insufficient diffraction data and the high pseudosymmetry of the structure, it is not possible at this point to determine with certainty the specific arrangement of the water molecules in the channels. When the Fourier transformation method is used to calculate the growth form of the hemihydrate (x = 0.5), the calculated crystal form corresponds to the observed form only when the trigonal structural symmetry is largely retained. During dehydration of gypsum or, conversely, during the setting process of hemihydrate, heteroepitaxial growths of hemihydrate are observed on gypsum, or gypsum is grown heteroepitaxially on hemihydrate. The (100) faces of the hemihydrate and (010) of gypsum for the most part run parallel. Using diffraction and spectroscopic methods, it can be shown that a structural difference exists between α- and β-hemihydrates, and that this difference probably accounts for the different setting behaviours. It is in this context that the presence of oxonium ions, particularly in β-hemihydrate, found in NMR experiments is of interest. Textural studies indicated that the arrangement of gypsum crystals found in hardened gypsum is determined by the hemihydrate. Citing Literature Volume37, Issue10October 2002Pages 1075-1087 RelatedInformation