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The Crystal Structure of Boehmite

Published online by Cambridge University Press:  01 July 2024

Gary G. Christoph ,
Charles E. Corbató ,
Douglas A. Hofmann  and
Rodney T. Tettenhorst
Gary G. Christoph
Affiliation:
The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, USA
Charles E. Corbató
Affiliation:
The Ohio State University, Columbus, Ohio 43210 Department of Geology and Mineralogy, USA
Douglas A. Hofmann
Affiliation:
The Ohio State University, Columbus, Ohio 43210 Department of Geology and Mineralogy, USA
Rodney T. Tettenhorst*
Affiliation:
Department of Geology and Mineralogy, USA
*
3Correspondence and reprint requests should be sent to R. Tettenhorst.
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Abstract

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The crystal structure of a synthetic boehmite sample has been refined to an R of 0.047 in the space group Amam from X-ray powder diffraction data. Inclusion of hydrogen atoms and/or refinement in the space group A21am gave poorer results. Cell dimensions were determined as a = 3.6936 (± 0.0003), b = 12.214 (± 0.001), c = 2.8679 (± 0.0003) Å. All Al-O(OH) distances lie between 1.88 and 1.91 Å. Shared octahedral edges are 2.51–2.52 Å, and unshared octahedral edges are 2.86–2.87 Å, in excellent agreement with those for layered silicates. The O-H … O distance between contiguous octahedral sheets is 2.71 Å. The computed X-ray pattern matches closely with the experimental pattern, indicating the degree to which the crystal structure has been determined.

Резюме

Резюме

Кристаллическая структура образца синтетического бемита была рафинирована до R равном 0,047 в пространственной группе Amam по данным порошкового метода рентгеноструктурного анализа. При включении водородных атомов и/или рафинировании в пространственной группе А21 am были получены худшие результаты. Были определены следующие размеры ячейки: а = 3,6936 (± 0,0003), b = 12,214 (± 0,001), с = 2,8679 (± 0,0003) А, Все расстояния АІ-О(ОН) лежат в пределах от 1,88 до 1,91 Å. Длина общих октаэдрических ребер 2,50–2,52 Å, длина необщих ребер 2,86–2,87 Å, в прекрасном соответствии с длинами ребер слойных силикатов. Расстояние О-Н... О между смежными пластинами 2,71 Å. Вычисленная рентгеновская модель хорошо согласуется с экспериментальной моделью, что указывает до какой степени определена кристаллическая структура.

Resümee

Resümee

Durch Röntgenpulverdiagramme wurde die Kristallstruktur eines synthetischen Boehmiten verfeinert bis zu R 0,047, in der Raumgruppe Amam. Einschluß von Wasserstoffatomen und/oder Verfeinern in der Raumgruppe A21 am ergab nicht so gute Resultate. Zelldimensionen wurden bestimmt: a = 3,6936 (± 0,0003), b = 12,214 (± 0,001), und c = 2,8679 (± 0,0003) Å. Alle Al-O(OH) Abstände sind zwischen 1,88 und 1,91 Å. Gemeinsame Kanten sind 2,50–2,52 Å und nicht geteilte Kanten sind 2,86-2,87 Å, was gut mit den Werten von Schichtsilikaten übereinstimmt. Der O-H... O Abstand zwischen benachbarten oktahedrischen Platten ist 2,71 Å. Errechnete röntgenmuster stimmen mit den experimentellen Daten überein, was auf das Ausmaß hindeutet, zu dem die Kristallstruktur bestimmt wurde.

Résumé

Résumé

La structure cristalline d'un échantillon d'une boehmite synthétique a été rafinée à un R de 0.047 dans le groupe d'espace Amam de données de diffraction aux rayons-X. L'inclusion d'atomes d'hydrogène et/ou le raffinement dans le groupe d'espace A21 am a donné de moins bons résultats. Les dimensions de maille ont été déterminées: a = 3.6936 (± 0.0003), b = 12.214 (± 0.001), et c = 2.8679 (± 0.0003) Å. Toutes les distances Al-O(OH) se trouvent entre 1.88 et 1.91 Å. Les bords octaédriques communs sont 2.50–2.52 Å, et les bords octaédriques non-communs sont 2.86–2.87 Å, en excellent accord avec ceux des silicates interstratifiés. La distance O-H... O entre des couches octaédriques contiguës est 2.71 Å. Le cliché de rayon-X calculé est très proche du cliché expérimental, indiquant le degré auquel la structure cristalline a été déterminée.

Keywords

BoehmiteCrystal StructureO-OH DistancesPowder X-ray DiffractionSynthesis
Type
Research Article
Information
Clays and Clay Minerals , Volume 27 , Issue 2 , April 1979 , pp. 81 - 86
Copyright
Copyright © 1979, The Clay Minerals Society

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