Clay Minerals · 1994 · 148 citations · 22 references
Natural SciencesChemistryMaterials ScienceInorganic ChemistryMaterials CharacterizationMineralogyClay MineralogyMineral ChemistryMineral GeochemistryMineral IdentificationSilicate MineralogySilicate MineralsClay Mineral ChemistryClay Mineral Crystal ChemistryClay Mineral CrystallographyClay Mineral ReactionsSilicate ChemistrySilicate Crystal StructuresSilicate Mineral ChemistrySilicate Structural Topology
Abstract The JP (Jelšový Potok, Slovakia) and SWy-1 (Wyoming, USA) montmorillonites were treated in 6 m HCl at 95°C. The rates of dissolution of tetrahedral and octahedral Al (Al tet and Al oct ) are comparable. Aluminium in the tetrahedral sheets was also identified in both untreated samples by 29 Si MAS NMR spectroscopy. About 12% of total Si in SWy-1 was found to be bound in quartz. Traces of undecomposed montmorillonite and a small amount of Al tet in the three-dimensional SiO 4 framework were found in the reaction product of montmorillonite decomposition. Three different types of structural units were identified in acid-treated samples: Q 4 (OAl) units of amorphous silica with three-dimensional crosslinked framework; (SiO) 3 SiOH units, remaining as a result of poor-ordering of the framework without the possibility of cross-linking; and Q 4 (1A1) units.
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High-resolution solid-state NMR of silicates and zeolites
B. Boddenberg · Applied Catalysis · 1988 · 1.8K citations