Tetrahedral-Atom 3-Ring Groupings in One-Dimensional Inorganic Chains: Be2AsO4OH-4H2O and Na2ZnPO4OH-7H2O.

摘要

The 'zeolitic' MXO4-based framework (M = Zn, Be, X = P, As) structure field has recently been shown to be a very extensive one by ourselves and others. A seemingly general feature of these new zeolitic (Zn/Be,P/As,O)-framework phases is a preference for a 1:1 M to X ratio and strict alternation of MO4 and XO4 tetrahedra, akin to a 'Lowenstein's rule' Al-O-Al avoidance and consequent Si/Al Tetrahedral alternation for 1:1 Si to Al ratio aluminosilicate phases. This feature would appear to militate against Zn/Be,P/As,O molecular sieves with odd- as opposed to even-membered ring systems, and also against phases whose M:X ratio is non-unity. We describe the preparations, structures and properties of two new phases; a zincophosphate, Na2ZnPO4OH(dot)7H2O (NaZnPO), and a berylloarsenate, Be2AsO4OH(dot)4H2O (BeAsO), which are non-zeolitic, but contain 1-dimensional chains, whose building blocks include tetrahedral 3-rings.