The use of Monte Carlo methods to determine the distribution of Al and Si cations in framework aluminosilicates from29Si MAS NMR data

Abstract

A Monte Carlo method was developed to determine the distribution of Al and Si cations from 29SiMAS NMR data for framework aluminosilicates. The method was used to analyze data obtained from Cs-exchanged leucite in its high-temperature cubic phase and from cubic analcime samples. It was also used to determine the number of AI-O-Allinkages in cordierite for different degrees of Al-Si order. The results for cordierite were correlated with the calorimetric data of Carpenter et al. (1983) to estimate the energy for the reaction (AI-O-Al) + (Si-O-Si) ~ 2(AI-O-Si) of -40 kJ/mol.