Crystal structures of Boro-AFm and sBoro-AFt phases
- Commissariat a l'Energie Atomique et aux Energies Alternatives, CEA DEN/DTCD/SPDE, F-30207 Bagnols sur Ceze (France)
- Clermont Universite, ENSCCF, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France)
- Clermont Universite, Universite Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France)
- LMCPA, Universite de Valenciennes et du Hainaut Cambresis, 59600 Maubeuge (France)
- Centre Commun de Mesure RMN, Universite Lille1 Sciences et Technologies, Cite Scientifique 59655 Villeneuve d'Ascq Cedex (France)
- EM Douai, MPE-GCE, 59508 Douai (France)
Crystal structures of boron-containing AFm (B-AFm) and AFt (B-AFt) phases have been solved ab-initio and refined from X-ray powder diffraction. {sup 11}B NMR and Raman spectroscopies confirm the boron local environment in both compounds: three-fold coordinated in B-AFm corresponding to HBO{sub 3}{sup 2-} species, and four-fold coordinated in B-AFt corresponding to B (OH){sub 4}{sup -} species. B-AFm crystallizes in the rhombohedral R3{sup Macron }c space group and has the 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}CaHBO{sub 3}{center_dot}12H{sub 2}O (4CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}1/2B{sub 2}O{sub 3}{center_dot}12.5H{sub 2}O, C{sub 4}AB{sub 1/2}H{sub 12.5}) general formulae with planar trigonal HBO{sub 3}{sup 2-} anions weakly bonded at the centre of the interlayer region. One HBO{sub 3}{sup 2-} anion is statistically distributed with two weakly bonded water molecules on the same crystallographic site. B-AFt crystallizes in the trigonal P3cl space group and has the 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}Ca(OH){sub 2}{center_dot}2Ca(B (OH){sub 4}){sub 2}{center_dot}24H{sub 2}O (6CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}2B{sub 2}O{sub 3}{center_dot}33H{sub 2}O, C{sub 6}AB{sub 2}H{sub 33}) general formulae with tetrahedral B (OH){sub 4}{sup -} anions located in the channel region of the structure. All tetrahedral anions are oriented in a unique direction, leading to a hexagonal c lattice parameter about half that of ettringite.
- OSTI ID:
- 22149350
- Journal Information:
- Cement and Concrete Research, Vol. 42, Issue 10; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0008-8846
- Country of Publication:
- United States
- Language:
- English
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