An Open‐Framework Germanate with Polycubane‐Like Topology

Body‐centered Ge ₉ parallelepiped building blocks form the basis of the structure of [Ge₉O₁₈(OH)₄]⋅2 (H₂ppz)⋅0.5 (H₂O) (ASU‐14, ppz=piperazine). In this new structure type for an open‐framework germanate (see picture for a section of the structure) the building blocks are linked together at each of their eight vertices to give the rare polycubane topology with an intersecting channel system of ten‐ and eight‐membered rings (pore sizes 5×6 and 4×4 Ų, respectively) in which the piperazinium cations and water molecules reside.