Synthesis and Structure of an Aluminophosphate Built from 3-Rings

By reacting a pre-made aluminophosphate (ALPO, P:Al = 0.9) gel with an aqueous tripropylamine solution of KOH and TMAOH, we have synthesized a new porous 3D crystalline structure (PSU-2) under high pH conditions. Single-crystal structure analysis shows that the orthorhombic crystal (Pnna with cell constants of a = 12.741 Å, b = 10.2211 Å, c = 6.2239 Å) is built from two different pairs of 3-rings of P tetrahedra and Al octahedra. Associated phases include ALPO analogues of the zeolites sodalite, analcime, and natrolite, the last not hitherto reported in an ALPO composition. The silicon-containing PSU-2 (SAPO) could not be made from an analogous SAPO gel.