The frameworks of zeolites and related crystalline microporous oxide materials, such as aluminophosphates, silicoaluminophosphates and metaloaluminophosphates, are built up of tetrahedrally coordinated (e.g., Si, Al, P) atoms. Microporous structures comprised entirely of octahedral sites are also known, encompassing manganese oxides (OMS materials, Suib 1998) and phases with composition Na2Nb2−xMxO6−x(OH)x•H2O, where M = Ti, Zr, and 0< x ≤ 0.4 (SOMS solids; Nyman et al. 2001, 2002). Mixed octahedral-pentahedral-tetrahedral microporous (OPT) siliceous frameworks have been much studied since the early 1990s (Rocha and...

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