Synthesis and characterization of new sodalites, cancrinites and their intermediate phase

Abstract

The thermal behavior and occuring phase transitions of three sodalites, a permanganate-, a perrhenate and a mixed permanganate/perrhenate-sodalite are investigated. Below 300 K a loss of dynamic motion of the templating anions could be observed, causing a phase transition of perrhenate-sodalite. At elevated temperatures all sodalites show a phase transition to the fully expanded structure (P-43n to Pm-3n). At 900 K the permangante-sodalite shows a second phase transition to P23.Further a comprehensive study on cancrinites containing different divalent tetrahedral coordinated anions (XO4 2-; X = Mn, Cr, Se, Mo, W) and their effect on the thermal behavior is performed. Thirdly, a structural investigation of the one-dimensional disordered Intermediate phase is carried out. By correlating the lattice parameter c with the existing zeolite-cages and the chemical composition of the sample the structure of the intermediate phase could be modeled.