A new type of interpenetration involving enmeshed independent square grid sheets. The structure of diaquabis-(4,4′-bipyridine)zinc hexafluorosilicate

Zn(4,4′-bipy)2SiF6·2H2O (4,4′-bipy = 4,4′-bipyridine) consists of two perpendicular and equivalent stacks of infinite, essentially square grid [Zn(H2O)2(4,4′-bipy)2]n2n+ sheets, which interpenetrate so that any particular sheet has an infinite number of perpendicular ones enmeshed or concatenated with it.