Revisiting the structure of the germanate zeotype ASU-7 (ASV)

The structure of the germanate zeotype material ASU-7 has been redetermined (tetragonal, space group P4/mnc, a = 12.4222(5) Å c = 14.4815(3) Å, V = 2234.66(14) Å3, R1 = 0.0289 and wR2 = 0.0762 for 867 (I > 2σ(I)) reflections) and shown to possess an ordered framework with a regular arrangement of the constituent double four ring units. The regular arrangement of the constituent rectangular prism-shaped double four ring units results in two, subtly different, 12-membered rings channels being defined along the crystallographic c-axis.