Routes to Rare Zeolites Zeolites are microporous crystalline solids with well-defined structures. Although many naturally occurring ones have been obtained in laboratory synthesis, some have remained elusive. One of these, boggsite, is of interest for catalytic reactions because it has large channels defined by rings of 10 or 12 atoms that intersect within its crystalline lattice. Simancas et al. (p. 1219 ) report the synthesis of boggsite by using phosphazenes as the organic groups that directed the formation of rings during synthesis. These reagents can be readily modified—a feature that should allow greater flexibility in synthesis routes.