Hydrothermal synthesis and low temperature crystal structure of an ammonium beryllophosphate with the merlinoite topology

An ammonium beryllophosphate (BeP-MER1) with the merlinoite framework topol ogy has been made by the hydrothermal synthesis. Similar to the mineral mer linoite, BeP-MER1 belongs to the orthorhombic space group, but its unit cel l is metrically tetragonal. The framework of a merlinoite structure such as BeP-MER1 can be viewed as the body-centered tetragonal packing of double 8 -rings or the stacking of 4.8.8 nets along the c-axis. BeP-MER1 has three-d imensional, intersecting 8-ring channels along the crystallographic [001], [110] and [1 (1) over bar 0] directions. The sites of extra-framework speci es are located, but the distribution of H2O and NH4+ among these sites are not unambiguously determined. A summary of beryllophosphate zeolite structu res provides an interesting comparison among hydrous and anhydrous alkali m etal templated beryllophosphate phases. (C) 1998 Elsevier Science B.V. All rights reserved.