Structure of V2O5•nH2O xerogel solved by the atomic pair distribution function technique

A long-standing issue regarding the local and long-range structure Of V2O5.nH(2)O xerogel has been successfully addressed. The full three-dimensional structure of the lamellar turbostratic V2O5.nH(2)O xerogel was determined by the atomic pair distribution function technique. We show that on the atomic scale the slabs of the xerogel can be described well as almost perfect pairs (i.e., bilayers) of single V2O5 layers made of square pyramidal VO5 units. These slabs are separated by water molecules and stack along the z-axis of a monoclinic unit cell (space group C2/m) with parameters a = 11.722(3) Angstrom, b = 3.570(3) Angstrom, c = 11.520(3) Angstrom, and beta = 88.65degrees. The stacking sequence shows signatures of turbostratic disorder and a structural coherence limited to 50 Angstrom.