Metal fluoride nanotubes featuring square-planar building blocks in a high-pressure polymorph of AgF2.

At a pressure of ca. 15 GPa, AgF2 transforms to an unprecedented orthorhombic polymorph featuring an array of tubular subunits which are built of corner sharing [AgF4] squares. This seems to be the first type of a metal fluoride nanowire and also the only one showing rigid square planar rather than common hexagonal or octahedral moieties.