Mariana Derzsi, Wojciech Grochala, University of Warsaw, Poland, Viktor V. Struzhkin, Carnegie Institution of Washington, Washington, D.C., USA, and colleagues have discovered a high-pressure polymorph of AgF2. The compound is the first example of a metal fluoride nanowire.
The team subjected AgF2, which has a crystal structure featuring AgF4 squares, to pressures above 15 GPa using a diamond anvil cell. The transformation was monitored using powder X-ray diffraction. The researchers found that the layered low-pressure AgF2 structure was converted to a quasi-1D nanotubular structure, composed of “stacked” square planar AgF4 units. The nanotubes are densely packed in the crystal lattice, which makes the structure stable at high pressures.
Due to the presence of the strongly electron-deficient Ag(II) cation, the team proposes that the material could have interesting magnetic and electronic properties. Density functional theory (DFT) calculations suggest that polymorph could be stable in a pressure range from ambient up to 80 GPa.
- Metal fluoride nanotubes featuring square-planar building blocks in a high-pressure polymorph of AgF2,
A. Grzelak, J. Gawraczyński, T. Jaroń, D. Kurzydłowski, Z. Mazej, P. J. Leszczyński, V. B. Prakapenka, M. Derzsi, V. V. Struzhkin, W. Grochala,
Dalton Trans. 2017.