Characterization of Silanol Groups in Protonated Magadiite by 1H and 2H Solid-State Nuclear Magnetic Resonance
Silanol groups in protonated magadiite (H-magadiite) were characterized by 1H and 2H solid-state nuclear magnetic resonance (NMR). H-magadiite and deuterated (D) magadiite were synthesized by the treatment of Na-rich magadiite with 0.2 N HC1 and 0.2 N DC1, respectively. In the ’H NMR spectrum measured at room temperature, silanol groups of H-magadiite showed two signals at 3.75 and 5.70 ppm, indicating that two types of silanol groups were present. The ratio of silanol groups associated with strong hydrogen bonding (5.70 ppm) to those with weaker hydrogen bonding (3.75 ppm) was 2 to 1. The 2H NMR spectra of deuterated magadiite were measured in the temperature range from 150 to 440 K. In the spectra measured at temperatures below 294 K, silanol groups showed Pake doublet patterns. These patterns were composed of two components corresponding to the two types of silanol groups shown in the ‘H NMR analysis. Both silanol groups produced wobbling motions with increasing temperature. Above 294 K, the profile of the Pake doublet pattern was transformed gradually to a near triangular pattern, indicating that the silanol groups underwent other motions also, such as a two-site jump.
Preparation and characterization of silylated-magadiites
Abstract Organic modification of a layered silicate, magadiite (the ideal formula is Na 2 Si 14 O 29 · n H 2 O), was conducted by the reaction between the interlayer hydroxyl groups of magadiite and organochlorosilanes (trimethylchrolosilane triethylchlorosilane, triisopropylchlorosilane, butyldimethylchlorosilane, octyldimethylchlorosilane, and octadecyldimethylchlorosilane). By utilizing the dodecyltrimethylammonium-exchanged magadiite as the intermediate, bulky organosilyl groups have successfully been introduced into the interlayer space of magadiite. The silylation of the interlayer silanol groups of layered silicates may lead to novel functional inorganic–organic supramolecular systems alternative to the intercalation compounds formed by ion exchange reactions.
Die hydrothermale Kristallisation des Magadiits. 1. Die Kristallisationskinetik ‐ Möglichkeiten ihrer Beschreibbarkeit
Gegenstand der Arbeit ist die Synthese des Natriumsilikathydrates (NaSH) Magadiit im ternaren System Na2O · SiO2 · H2O. Die Kinetik der Kristallisation wird verfolgt und durch physikalische und chemische Methoden charakterisiert. Auf Basis dieser Ergebnisse wird eine Modellvorstellung fur die Kristallisation des Magadiits entwickelt und angegeben. 
 
 
 
The Hydrothermal Magadiite Crystallisation. 1. The Kinetic of the Crystallisation - Possibilities of their Description 
 
 
 
The topic of this paper is the synthesis of the sodium-silicate hydrate (NaSH) magadiite within reaction mixtures of the ternary system Na2O · SiO2 · H2O. The crystallisation kinetics are studied and characterized by means of physical and chemical methods. As a result of this investigations a schematic model representation of the magadiit crystallisation is given.