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Title: Structure of Calcium Aluminate Decahydrate (CaAl2O4.10D2O) from Neutron and X-ray Powder Diffraction Data

Abstract

Calcium aluminate decahydrate is hexagonal with the space group P63/m and Z = 6. The compound has been named CaAl2O4{center_dot}10H2O (CAH10) for decades and is known as the product obtained by hydration of CaAl2O4 (CA) in the temperature region 273-288 K - one of the main components in high-alumina cements. The lattice constants depend on the water content. Several sample preparations were used in this investigation: one CAH10, three CAD10 and one CA(D/H)10, where the latter is a zero-matrix sample showing no coherent scattering contribution from the D/H atoms in a neutron diffraction powder pattern. The crystal structure including the positions of the H/D atoms was determined from analyses of four neutron diffraction powder patterns by means of the ab initio crystal structure determination program FOX and the FULLPROF crystal structure refinement program. Additionally, eight X-ray powder diffraction patterns (Cu K[alpha]1 and synchrotron X-rays) were used to establish phase purity. The analyses of these combined neutron and X-ray diffraction data clearly show that the previously published positions of the O atoms in the water molecules are in error. Thermogravimetric analysis of the CAD10 sample preparation used for the neutron diffraction studies gave the composition CaAl2(OD)8(D2O)2{center_dot}2.42D2O. Neutron and X-ray powder diffractionmore » data gave the structural formula CaAl2(OX)8(X2O)2{center_dot}[gamma]X2O (X = D, H and D/H), where the [gamma] values are sample dependent and lie between 2.3 and 3.3.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
959548
Report Number(s):
BNL-82534-2009-JA
TRN: US1005757
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica Section B: Structural Science; Journal Volume: 63
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 43 PARTICLE ACCELERATORS; ALUMINATES; ATOMS; CALCIUM; CEMENTS; COHERENT SCATTERING; CRYSTAL STRUCTURE; DIFFRACTION; HYDRATION; NEUTRON DIFFRACTION; NEUTRONS; SAMPLE PREPARATION; SPACE GROUPS; SYNCHROTRONS; THERMAL GRAVIMETRIC ANALYSIS; WATER; X-RAY DIFFRACTION; national synchrotron light source

Citation Formats

Christensen,A., Lebech, B., Sheptyakov, D., and Hanson, J. Structure of Calcium Aluminate Decahydrate (CaAl2O4.10D2O) from Neutron and X-ray Powder Diffraction Data. United States: N. p., 2007. Web. doi:10.1107/S0108768107035136.
Christensen,A., Lebech, B., Sheptyakov, D., & Hanson, J. Structure of Calcium Aluminate Decahydrate (CaAl2O4.10D2O) from Neutron and X-ray Powder Diffraction Data. United States. doi:10.1107/S0108768107035136.
Christensen,A., Lebech, B., Sheptyakov, D., and Hanson, J. Mon . "Structure of Calcium Aluminate Decahydrate (CaAl2O4.10D2O) from Neutron and X-ray Powder Diffraction Data". United States. doi:10.1107/S0108768107035136.
@article{osti_959548,
title = {Structure of Calcium Aluminate Decahydrate (CaAl2O4.10D2O) from Neutron and X-ray Powder Diffraction Data},
author = {Christensen,A. and Lebech, B. and Sheptyakov, D. and Hanson, J.},
abstractNote = {Calcium aluminate decahydrate is hexagonal with the space group P63/m and Z = 6. The compound has been named CaAl2O4{center_dot}10H2O (CAH10) for decades and is known as the product obtained by hydration of CaAl2O4 (CA) in the temperature region 273-288 K - one of the main components in high-alumina cements. The lattice constants depend on the water content. Several sample preparations were used in this investigation: one CAH10, three CAD10 and one CA(D/H)10, where the latter is a zero-matrix sample showing no coherent scattering contribution from the D/H atoms in a neutron diffraction powder pattern. The crystal structure including the positions of the H/D atoms was determined from analyses of four neutron diffraction powder patterns by means of the ab initio crystal structure determination program FOX and the FULLPROF crystal structure refinement program. Additionally, eight X-ray powder diffraction patterns (Cu K[alpha]1 and synchrotron X-rays) were used to establish phase purity. The analyses of these combined neutron and X-ray diffraction data clearly show that the previously published positions of the O atoms in the water molecules are in error. Thermogravimetric analysis of the CAD10 sample preparation used for the neutron diffraction studies gave the composition CaAl2(OD)8(D2O)2{center_dot}2.42D2O. Neutron and X-ray powder diffraction data gave the structural formula CaAl2(OX)8(X2O)2{center_dot}[gamma]X2O (X = D, H and D/H), where the [gamma] values are sample dependent and lie between 2.3 and 3.3.},
doi = {10.1107/S0108768107035136},
journal = {Acta Crystallographica Section B: Structural Science},
number = ,
volume = 63,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}