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Clays and Clay Minerals

, Volume 30, Issue 4, pp 297–305 | Cite as

Structural Model for Benzidine-Vermiculite

  • P. G. Slade
  • M. Raupach
Article

Abstract

A combination of X-ray diffraction, infrared, and chemical data has established that the ion exchange of vermiculite with singly charged benzidine cations in an aqueous solution at pH 1.6 results in a black, highly ordered benzidine-vermiculite intercalate. The intercalate has a basal spacing of 19.25 Å and a primitive unit cell with “a” and “b” edges parallel and equal to those of vermiculite. The number of benzidine molecules per cell is equal to its electric charge. In this structure the benzidine molecules are steeply inclined to the silicate surfaces and close-packed within domains. The domains contain alternating rows of benzidine cations; from row to row the planes are either approximately parallel or perpendicular to the (120) plane, but along any one row the planes of the aromatic rings are parallel to each other. Hydrogen bonding operates between amine nitrogens and surface oxygens.

Key Words

Benzidine Hydrogen bonding Intercalation Vermiculite X-ray diffraction 

Резюме

Комбинация данных по рентгеновской порошковой дифракции, инфракрасном и химическом анализах показала, что результатом обмена ионов вермикулита с однозаряженными бензидиновыми катионами в водных растворах при рН = 1,6 является черный, сильно упорядоченный, прослоеннчй бензидино-вермикулит. Этот продукт миеет промежуток 19,25 А и примитивную элементарную ячейку с краями “а” и “Ь,” параллельными и равными по величине краям в вермикулите. Число молекул бензидина в ячейке равно его электрическому заряду. В этой структуре молекулы бензидина круто наклонены к силикатовым поверхностям и плотно упакованы внутои областей. Области содержат переменные ряды бензидиновых катионов; от ряда до ряда плоскости или приблизительно параллельны или перпендикулярны к плоскости (120), но вдоль любого ряда плоскости ароматических колец параллельны между собой. Водородная связь действует между аминовыми атомами азота и поверхностными атомами кислорода. [Е.С.]

Resümee

Eine Kombination von Röntgendiffraktion-, Infrarot-, und chemischen Daten hat gezeigt, daß der Ionenaustausch von Vermiculit mit einfach geladenen Benzidinkationen in einer wässrigen Lösung bei pH 1,6 zu einer schwarzen, gut geordneten Benzidin-Vermiculit Wechsellagerung führt. Die Wechsellagerung hat einen Basisabstand von 19,25 Å und eine primitive Elementarzelle mit “a” und “b” Kanten parallel und gleich denen von Vermiculit. Die Zahl der Benzidinmoleküle pro Elementarzelle entspricht der elektrischen Ladung. In dieser Struktur sind die Benzidinmoleküle steil zu den Silikatoberflächen und in dichtbesetzten Domänen angeordnet. Diese Domänen enthalten abwechselnde Reihen von Benzidinkationen; von Reihe zu Reihe sind die Benzidinebenen entweder nahezu parallel oder senkrecht zur (120)-Fläche angeordnet, aber innerhalb einer Reihe sind die Ebenen der aromatischen Ringe zueinander parallel. Wasserstoffbrückenbindung besteht zwischen Aminstickstoffen und den Oberflächensauerstoffen. [U.W.]

Résumé

La combinaison de données de diffraction aux rayons-X et d’analyse infrarouge et chimique a établi que l’échange des ions de vermiculite avec les cations de benzidine simplement chargés dans une solution aqueuse à un pH de 1,6 resulte en un intercalate noir benzidine-vermiculite très ordonné. L’intercalate a un espacement de base de 19,25 Å et une maille primitive ayant les côtés “a” et “b” parallèles et égaux à ceux de la vermiculite. Le nombre de molécules de benzidine par maille est égal à sa charge électrique. Dans cette structure, les molécules de benzidine sont fortement inclinées vers les surfaces silicates et sont arrangées de manière très compacte endéans les domaines. Les domaines contiennent des rangées alternantes de cations benzidine; d’une rangée à l’autre, les surfaces planes sont soit approximativement parallèles, soit perpendiculaires à la surface plane (120), mais le long d’une seule rangée, les surfaces planes contenant les anneaux aromatiques sont parallèles l’une à l’autre. La liaison d’hydrogène se passe entre les nitrogènes aminés et les surfaces oxygènes. [D.J.]

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Copyright information

© The Clay Minerals Society 1982

Authors and Affiliations

  • P. G. Slade
    • 1
  • M. Raupach
    • 1
  1. 1.CSIRO Division of SoilsGlen OsmondAustralia

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