The crystal chemistry of paulingite
Passaglia, Elio; Gualtieri, Alessandro F.; Marchi, Eugenia
European Journal of Mineralogy Volume 13 Number 1 (2001), p. 113 - 119
published: Jan 31, 2001
ArtNo. ESP147051301011, Price: 29.00 €
The crystal chemistry of the uncommon zeolite paulingite, [(K,Na,Ca0.5,Ba0.5)10(Al10Si32O84) · 30 H2O; Z = 16] is updated and revised on the basis of chemical compositions and cell constants of ten samples representative of almost all the occurrences known to date. The framework cation content, defined as R = Si/(Si+Al), shows slight variations ranging from 0.73 to 0.79. The extraframework cations are mainly K, Ca, Na, and minor Ba. Mg and Sr are absent or negligible. The K, Ca and Na contents are extremely variable so that all three types of cation-dominance are found. The cell constant shows small variations (from 35.03 to 35.24 Å) and no significant correlation with the chemical variables. The (K+Na) content is positively correlated with the Si content, and a strong negative correlation between Ca and Na is found. The water content is variable and independent upon the chemical parameters. The dehydration process of the Ca-dominant sample is significantly different from that of both K- and Na-dominant samples.